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Pancreatobiliary Pathology Society Journal Watch |
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Last Update on 2020-12-08 |
September - October 2020 |
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Welcome to the PBPath Journal Watch!
This bi-monthly journal watch features exciting recently published pancreas and biliary pathology articles that will provide up to date medical knowledge in our field. These articles will be showcased in several convenient categories, including surgical pathology, cytopathology, molecular pathology, pancreas, gallbladder, bile ducts, and ampulla among others. The articles in each category are in no particular order. See the list of journals we search regularly here. Previous months’ issues may be found in our archive and you may see drafts of the upcoming issue here.
We encourage members to actively participate by recommending new articles and providing feedback using the forms provided below.{target="_self"}
We hope that you will enjoy the new PBPath Journal Watch!
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- **Reassessment of the Optimal Number of Examined Lymph Nodes in Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma**
Annals of surgery 2020 Nov;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33177357
OBJECTIVE: To reappraise the optimal number of examined lymph nodes (ELN) in pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC). SUMMARY BACKGROUND DATA: The well-established threshold of 15 ELN in PD for PDAC is optimized for detecting one positive node (PLN) per the previous 7 edition of the AJCC staging manual. In the framework of the 8 edition, where at least four PLN are needed for an N2 diagnosis, this threshold may be inadequate for accurate staging. METHODS: Patients who underwent upfront PD at two academic institutions between 2000 and 2016 were analyzed. The optimal ELN threshold was defined as the cut-point associated with a 95% probability of identifying at least 4 PLN in N2 patients. The results were validated addressing the N-status distribution and stage migration. RESULTS: Overall, 1218 patients were included. The median number of ELN was 26 (IQR 17-37). ELN was independently associated with N2-status (OR 1.27, p < 0.001). The estimated optimal threshold of ELN was 28. This cut-point enabled improved detection of N2 patients and stage III disease (58% versus 37%, p = 0.001). The median survival was 28.6 months. There was an improved survival in N0/N1 patients when ELN exceeded 28, suggesting a stage migration effect (47 versus 29 months, adjusted HR 0.649, p < 0.001). In N2 patients, this threshold was not associated with survival on multivariable analysis. CONCLUSION: Examining at least 28 LN in PD for PDAC ensures optimal staging through improved detection of N2/stage III disease. This may have relevant implications for benchmarking processes and quality implementation.
- **Alterations in Ki67 Labeling Following Treatment of Poorly Differentiated Neuroendocrine Carcinomas: A Potential Diagnostic Pitfall**
The American journal of surgical pathology 2020 Nov;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33177340
Assessment of the Ki67 index is critical for grading well-differentiated neuroendocrine tumors (WD-NETs), which can show a broad range of labeling that defines the WHO grade (G1-G3). Poorly differentiated neuroendocrine carcinomas (PD-NECs) have a relatively high Ki67 index, >20% in all cases and commonly exceeding 50%. After anecdotally observing PD-NECs with an unexpectedly low and heterogeneous Ki67 index following chemotherapy in 5 cases, we identified 15 additional cases of treated high-grade neuroendocrine neoplasms (HG-NENs). The study cohort comprised 20 cases; 11 PD-NECs, 8 mixed adenoneuroendocrine carcinomas, and 1 WD-NET, G3 from various anatomic sites (gastrointestinal tract, pancreas, larynx, lung, and breast). The Ki67 index was evaluated on pretreatment (when available) and posttreatment samples. Topographic heterogeneity in the Ki67 index was expressed using a semi-quantitative score of 0 (no heterogeneity) to 5 (>80% difference between maximal Ki67 and minimal Ki67 indices). Relative to the pretreatment group (n=9, mean Ki67 of 86.3%, range 80% to 100%), the neoplasms in the posttreatment group (n=20, mean Ki67 of 47.7%, range 1% to 90%) showed a significantly lower Ki67 index (18/20 cases). Of the 18 cases with a relatively low Ki67 index, 15 showed heterogeneous labeling (mean heterogeneity score of 2.3, range 1 to 5) and in 3 cases it was a homogeneously low. This phenomenon was observed in all subtypes of HG-NENs. In 6 cases, the alterations in Ki67 index following treatment were sufficient to place these HG-NENs in the WHO G1 or G2 grade, erroneously suggesting a diagnosis of WD-NET, and in 9 cases there was sufficient heterogeneity in the Ki67 index to suggest that a limited biopsy may sample an area of low Ki67, even though hotspot regions with a Ki67 index of >20% persisted. In 7 cases, the alterations in the Ki67 index were accompanied by morphologic features resembling a WD-NET. These observations suggest that there is a potential for misinterpretation of previously treated PD-NECs as WD-NETs, or for assigning a lower grade in G3 WD-NETs. While the prognostic significance of treatment-associated alterations in Ki67 index is unknown, awareness of this phenomenon is important to avoid this diagnostic pitfall when evaluating treated NENs.
- **Efficacy of EUS-guided FNB using a Franseen needle for tissue acquisition and microsatellite instability evaluation in unresectable pancreatic lesions**
BMC cancer 2020 Nov;20(1):1094
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33176750
BACKGROUND: The efficacy of immune checkpoint blockade in the treatment of microsatellite instability (MSI)-high tumors was recently reported. Therefore, the acquisition of histological specimens is desired in cases of unresectable solid pancreatic lesions (UR SPLs). This study investigated the efficacy of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using a Franseen needle for UR SPL tissue acquisition and MSI evaluation. METHODS: A total of 195 SPL patients who underwent EUS-guided fine-needle aspiration (EUS-FNA) or EUS-FNB (EUS-FNAB) between January 2017 and March 2020 were enrolled in this study. Among them, 89 SPL patients (FNB: 28, FNA: 61) underwent EUS-FNAB using a 22-G needle (UR SPLs: 58, FNB: 22, FNA: 36) (UR SPLs after starting MSI evaluation: 23, FNB: 9, FNA: 14). RESULTS: The puncture number was significantly lower with FNB than with FNA (median (range): 3 (2-5) vs 4 (1-8), P < 0.01, UR SPLs: 3 (2-5) vs 4 (1-8), P = 0.036). Histological specimen acquisition was more commonly achieved with FNB than with FNA (92.9% (26/28) vs 68.9% (42/61), P = 0.015, UR SPLs: 100% (22/22) vs 72.2% (26/36), P < 0.01). The histological specimen required for MSI evaluation was acquired more often with FNB than with FNA (88.9% (8/9) vs 35.7% (5/14), P = 0.03). CONCLUSIONS: EUS-FNB using a Franseen needle is efficient for histological specimen acquisition and sampling the required amount of specimen for MSI evaluation in UR SPL patients.
- **Comparative Effectiveness of Neoadjuvant Therapy and Upfront Resection for Patients with Resectable Pancreatic Adenocarcinoma: An Instrumental Variable Analysis**
Annals of surgical oncology 2020 Nov;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33174146
BACKGROUND: Neoadjuvant therapy (NAT) is increasingly being used in the management of patients with resectable pancreatic ductal adenocarcinoma (PDAC); however, there is a lack of evidence regarding the benefit among these patients. OBJECTIVE: The aim of this study was to evaluate overall survival (OS) in PDAC patients with resectable disease treated with NAT or upfront resection through instrumental variable (IV) analysis. DESIGN: A national cohort study of resectable PDAC patients in the National Cancer Data Base (2007-2015) treated with either upfront surgery or resection after NAT. Using multivariable modeling and IV methods, OS was compared between those treated with NAT and upfront resection. The IV was hospital-level NAT utilization in the most recent year prior to treatment. RESULTS: The cohort included 16,666 patients (14,012 upfront resection; 2654 NAT) treated at 779 hospitals. Among those treated with upfront resection, 59.9% received any adjuvant therapy. NAT patients had higher median (27.9 months, 95% confidence interval [CI] 26.2-29.1) and 5-year OS (24.1%, 95% CI 21.9-26.3%) compared with those treated with upfront surgery (median 21.2 months, 95% CI 20.7-21.6; 5-year survival 20.9%, 95% CI 20.1-21.7%). After multivariable modeling, NAT was associated with an approximately 20% decrease in the risk of death (hazard ratio [HR] 0.78, 95% CI 0.73-0.84), and this effect was magnified in the IV analysis (HR 0.61, 95% CI 0.47-0.79). CONCLUSIONS: In patients with resectable PDAC, NAT is associated with improved survival relative to upfront resection. Given the benefits of multimodality therapy and the challenges in receiving adjuvant therapy, consideration should be given to treating all PDAC patients with NAT.
- **Acinar cell induced autolysis is a frequent occurrence in CytoLyt-fixed pancreatic fine needle aspiration specimens: An analysis of 157 cytology samples**
Cancer cytopathology 2020 Nov;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33136337
BACKGROUND: Although 10% formalin is a standard preservative in pancreatic FNAs, the effect of CytoLyt on pancreatic tissue preservation has not been systematically explored. METHODS: Smears and cell blocks from CytoLyt-fixed (CF-CBs) and formalin-fixed (FF-CBs) pancreatic FNAs were blindly reviewed without knowledge of the fixative used, and the presence of tissue/tumor autolysis was noted. Controls included FF-CBs from pancreatic FNAs, CF-CBs from nonpancreatic FNAs, and 4 pancreatic FNAs with matched CF-CBs and FF-CBs. RESULTS: We found that 62 of 85 (73%) pancreatic FNAs with CF-CBs showed significant autolysis, which was most pronounced in acinar cells and/or tumor cells with benign acinar cells in the background, compared with 2 of 46 (4%) FF-CBs (P < .0001) and 3 of 26 (12%) CF-CBs from nonpancreatic FNAs (73% vs 12%; P < .0001). Of the 4 pancreatic FNAs with matched CF-CBs and FF-CBs, all 4 CF-CBs showed marked autolysis versus none of the matched FF-CBs. Of the 23 (27%) pancreatic FNAs with CF-CBs that did not show autolysis, 10 had no acinar cells, and 7 had only minute tissue fragments on CB. CONCLUSION: While CytoLyt is a useful fixative for nonpancreatic FNAs it is a suboptimal fixative for pancreatic FNAs and is associated with tissue/tumor autolysis in the majority of cases, influencing morphologic evaluation, and potentially immunocytochemical staining. Autolysis appears to be due to acinar enzymes whose effect is likely interrupted/inhibited by formalin fixation. Cytopathologists and cytotechnologists should be mindful of this pitfall and should avoid using CytoLyt as a fixative for pancreatic FNAs.
- **Clinical Implications of Pre- and Postoperative Circulating Tumor DNA in Patients with Resected Pancreatic Ductal Adenocarcinoma**
Annals of surgical oncology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33128119
BACKGROUND: The clinical implications of pre- and postoperative KRAS-mutated circulating tumor DNA (ctDNA) present in patients with pancreatic ductal adenocarcinoma (PDAC) have remained an unresolved issue. This study sought to investigate the clinical significance of pre- and postoperative ctDNA analyses and their impact on the prognosis of PDAC patients. METHODS: Digital droplet polymerase chain reaction detected ctDNA in pre- and postoperative plasma samples prospectively obtained from patients with resectable and borderline-resectable PDAC. Its associations with recurrence-free survival (RFS) and overall survival (OS) were analyzed. The patients were sorted according to the presence of pre- and postoperative ctDNA, and its ability to stratify prognosis was evaluated. RESULTS: The study analyzed 97 patients. Both pre- and postoperative ctDNA were detected in 9 patients, and neither was detected in 55 patients. Whereas 15 patients harbored only preoperative ctDNA, 18 patients had only postoperative ctDNA. The multivariate analysis showed that the presence of preoperative ctDNA was associated with poorer OS (P = 0.008) and that postoperative ctDNA was not associated with either RFS or OS. Survival did not differ significantly between the patients with a positive shift in ctDNA status and those without detectable pre- or postoperative ctDNA. CONCLUSIONS: For the patients with PDAC, the presence of preoperative ctDNA was significantly associated poor OS, whereas postoperative ctDNA was not associated with poor survival. A positive change in ctDNA did not affect patients' survival.
- **Concordance Between the Ki-67 Index Cutoff Value of 55% and Differentiation in Neuroendocrine Tumor and Neuroendocrine Carcinoma in Grade 3 Pancreatic Neuroendocrine Neoplasms**
Pancreas 2020 10;49(10):1378-1382
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33122528
OBJECTIVE: In 2017 and 2019, the World Health Organization defined grade 3 neuroendocrine tumors (G3 NETs) and neuroendocrine carcinoma (G3 NEC) in the pancreas. The validity of this classification remains to be verified. METHODS: Clinical data were collected and analyzed for 39 G3 pancreatic neuroendocrine neoplasms (PanNENs) patients between 2009 and 2018. RESULTS: The tumor-node-metastasis stage (P = 0.0260), differentiation (P = 0.0115), and Ki-67 index (P = 0.0371) are prognostic factors for G3 PanNENs by Kaplan-Meier survival analysis. Among 39 patients, 18 had a Ki-67 index of less than 55% and well-differentiated morphology (G3 NET) and 16 had a Ki-67 index of 55% or greater and poorly differentiated morphology (G3 NEC). Grade 3 neuroendocrine tumor had a significant better prognosis than G3 NEC (median overall survival time, 25 months [95% confidence interval, 10.854-39.146 months] vs 12 months [95% confidence interval, 6.316-17.684 months], P = 0.0164). Based on Cox regression analyses, tumor-node-metastasis stage (P = 0.016) was identified as the independent prognostic factor for G3 PanNENs. CONCLUSIONS: The upper Ki-67 index cutoff of 55% might be the best cutoff value to define G3 NETs and G3 NECs for G3 PanNENs. The World Health Organization 2017 and 2019 classification system for G3 PanNENs can identify high-risk patients with G3 PanNENs.
- **Lewis Antigen Phenotype and Survival of Patients With Pancreatic Cancer**
Pancreas 2020 10;49(10):1348-1354
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33122524
OBJECTIVES: The association of Lewis antigen phenotype with survival of patients with pancreatic ductal adenocarcinoma was investigated. METHODS: A total of 1187 patients diagnosed with pancreatic ductal adenocarcinoma were evaluated in a prospective cohort. Patients were classified into 3 different groups according to Lewis antigen phenotype: Lewis antigen (1) A positive [Le(a+b-)], (2) B positive [Le(a-b+)], and (3) negative [Le(a-b-)]. Risk of mortality was analyzed with Cox regression after adjusting for other predictors. RESULTS: The risk of mortality increased in the order of Le(a+b-), Le(a-b+), and Le(a-b-) [reference; hazard ratio (HR), 1.27; 95% confidence interval (CI)], 1.03-1.57; P = 0.02; and HR, 1.65; 95% CI, 1.31-2.09; P < 0.001] after adjusting for other predictors. Among patients with serum carbohydrate antigen (CA) 19-9 lower than 37 U/mL, the association seemed more apparent (reference; HR, 1.50; 95% CI, 0.77-2.29; P = 0.22; and HR, 2.10; 95% CI, 1.10-4.02; P < 0.02). CONCLUSIONS: The risk of mortality increased in the order of Le(a+b-), Le(a-b+), and Le(a-b-). The difference in prognosis according to the Lewis antigen phenotype was more pronounced in the low CA 19-9 group, which suggests that the Lewis antigen phenotype works as a biomarker predicting the prognosis of patients with pancreatic cancer with undetectable CA 19-9 level.
- **Low expression of DDX5 is associated with poor prognosis in patients with pancreatic ductal adenocarcinoma**
Journal of clinical pathology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33097588
AIMS: Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies. Hence, there is a need for new markers and treatment strategies. P68/DEAD box protein 5 (DDX5) is an ATP-dependent RNA helicase of the DEAD box protein family. It is a prognostic marker for several cancers. In this study, we aimed to evaluate the expression and clinical relevance of DDX5 in PDAC. METHODS: DDX5 expression in tissue microarray blocks containing 230 PDAC samples was examined using immunohistochemical analysis. DDX5 expression was considered high when more than 50% of the cells were stained and low when less than 50% of the cells were stained. We investigated the association between DDX5 expression and clinicopathological parameters, including patient survival. RESULTS: The nuclei of normal pancreatic ducts, normal acinar cells and PDAC cells were stained positive for DDX5 although the intensity and distribution of DDX5 expression varied. Islet cells showed strong and diffuse staining of DDX5. DDX5 expression was low and high in 148 (64.3%) and 82 cases (35.7%), respectively. Low DDX5 expression was significantly associated with an advanced pT factor (pT2-pT3: tumour size,>20 mm), lymphatic involvement, advanced tumour-node-metastasis (TNM) stage (stages IIB, III, and IV), and venous involvement. In addition, the multivariate analysis revealed that DDX5 expression is an independent prognostic factor for PDAC. CONCLUSION: These results suggest that DDX5 plays an important role in tumour invasiveness and PDAC prognosis.
- **The histopathology of SPINK1-associated chronic pancreatitis**
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.] 2020 Dec;20(8):1648-1655
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33097431
BACKGROUND: The identification of genetic risk factors for chronic pancreatitis, such as PRSS1, CFTR and SPINK1, provides the opportunity to define key pathologic hallmarks and etiologic-specific changes. For example, pancreata from PRSS1 and CFTR patients exhibit progressive lipomatous atrophy without significant fibrosis. Considering the pathology of SPINK1-associated pancreatitis is ill-defined, we examined the pancreata of SPINK1 patients with chronic pancreatitis. METHODS: Histologic sections after total pancreatectomy with islet autotransplantation and associated clinicopathologic data were collected from 28 patients with SPINK1 germline alterations. Clinical findings, germline data, anatomic anomalies and pathologic findings were descriptively evaluated. RESULTS: Patients ranged in age from 5 to 48 years (median, 21.6 years) with abdominal pain between 2 and 25 years (median, 5.8 years). Most patients were SPINK1 heterozygous and 14 (50%) had co-occurring CFTR (n = 12) and CTRC (n = 2) mutations. Other pancreatitis risk factors included anatomic anomalies (n = 9) and tobacco use (n = 1). Overall, 24 (86%) patients had additional pancreatitis-associated germline alterations, SPINK1 homozygosity, anatomic anomalies or environmental factors. Examination of pancreata revealed a sequential pattern of exocrine parenchymal loss and replacement by prominent fibrosis, dependent on the duration of abdominal pain. No malignancies were identified, but low-grade pancreatic intraepithelial neoplasia was present for 2 cases. CONCLUSIONS: Within this descriptive study, SPINK1-associated pancreatitis is characterized by parenchymal fibrosis and suggests divergent pathophysiologic mechanisms from PRSS1 and CFTR-associated pancreatitis. Moreover, SPINK1 patients frequently had additional etiologic factors that did not impact the development of pancreatic fibrosis and may implicate SPINK1 as a disease modifier gene.
- **Implications of Perineural Invasion on Disease Recurrence and Survival After Pancreatectomy for Pancreatic Head Ductal Adenocarcinoma**
Annals of surgery 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33086324
OBJECTIVE: To describe PNI and to evaluate its impact on disease-free (DFS) and overall survival (OS) in patients with resected pancreatic ductal adenocarcinoma (PDAC). SUMMARY OF BACKGROUND DATA: Although PNI is a prognostic factor for survival in many GI cancers, there is limited knowledge regarding its impact on tumor recurrence, especially in "early stage disease" (PDAC ≤20 mm, R0/N0 PDAC). METHODS: This multicenter retrospective study included patients undergoing PDAC resection between 2009 and 2014. The association of PNI with DFS and OS was analyzed using Cox proportional-hazards models. RESULTS: PNI was found in 87% of 778 patients included in the study, with lower rates in PDAC ≤20 mm (78.7%) and in R0/N0 tumors (70.6%). PNI rate did not differ between patients who underwent neoadjuvant therapy and upfront surgery (88% vs 84%, P = 0.08). Although not significant at multivariate analysis (P = 0.07), patients with PNI had worse DFS at univariate analysis (median DFS: 20 vs 15 months, P < 0.01). PNI was the only independent predictor of DFS in R0/N0 tumors (hazard ratio [HR]: 2.2) and in PDAC ≤20 mm (HR: 1.8). PNI was an independent predictor of OS in the entire cohort (27 vs 50 months, P = 0.01), together with G3 tumors, pN1 status, carbohydrate antigen (CA) 19.9 >37 and pain. CONCLUSIONS: PNI represents a major determinant of tumor recurrence and patients' survival in pancreatic cancer. The role of PNI is particularly relevant in early stages, supporting the hypothesis that invasion of nerves by cancer cells has a driving role in pancreatic cancer progression.
- **Endoscopic ultrasound acquired portal venous circulating tumor cells predict progression free survival and overall survival in patients with pancreaticobiliary cancers**
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.] 2020 Dec;20(8):1747-1754
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33082106
BACKGROUND AND AIMS: Despite recent advances, patients with pancreaticobiliary cancers have a poor prognosis. We previously demonstrated the efficacy of endoscopic ultrasound (EUS) guided acquisition of portal vein (PV) blood for enumeration of circulating tumor cells (CTCs). The aim of this study was to assess PV-CTCs as potential biomarkers for the assessment of progression-free (PFS) and overall survival (OS) in patients with pancreaticobiliary cancers. METHODS: 17 patients with biopsy-proven pancreaticobiliary malignancy were enrolled. CTCs were enumerated from both peripheral and PV blood. All patients were followed until death. PFS and OS were evaluated with the log-rank test and summarized with the use of Kaplan-Meier methods. Unadjusted and adjusted Cox-proportional hazards models were fitted to study the relationship between PV-CTCs and PFS and OS. RESULTS: After 3.5 years of follow-up, all patients had expired. PV-CTCs were detected in all patients (median PV-CTCs 62.0/7.5 mL (interquartile range [IQR] 17-132). The mean PFS in patients with PV-CTCs <185/7.5 mL was significantly longer than patients with PV-CTCs ≥185/7.5 mL (43.3 weeks vs. 12.8 weeks, log-rank p = 0.002). The mean OS in patients with PV-CTCs <185/7.5 mL was significantly longer than patients with PV-CTCs ≥185/7.5 mL (75.8 weeks vs. 29.5 weeks, log-rank p = 0.021). In an adjusted Cox-proportional hazards model, PV-CTCs were significant predictors of both PFS and OS (HR 1.004, p = 0.037; HR 1.004, p = 0.044 respectively). CONCLUSION: In this pilot and feasibility study, EUS-acquired PV-CTCs predicted PFS and OS. Our findings suggest that PV-CTCs can help provide important prognostic data for both providers and patients.
- **Epithelial Nr5a2 heterozygosity cooperates with mutant Kras in the development of pancreatic cystic lesions**
The Journal of pathology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33079429
Cystic neoplasms of the pancreas are an increasingly important public health problem. The majority of these lesions are benign but some progress to invasive pancreatic ductal adenocarcinoma (PDAC). There is a dearth of mouse models of these conditions. The orphan nuclear receptor NR5A2 regulates development, differentiation, and inflammation. Germline Nr5a2 heterozygosity sensitizes mice to the oncogenic effects of mutant Kras in the pancreas. Here, we show that - unlike constitutive Nr5a2+/- mice - conditional Nr5a2 heterozygosity in pancreatic epithelial cells, combined with mutant Kras (KPN+/- ), leads to a dramatic replacement of the pancreatic parenchyma with cystic structures and an accelerated development of high-grade PanINs and PDAC. Timed histopathological analyses indicated that in KPN+/- mice PanINs precede the formation of cystic lesions and the latter precede PDAC. A single episode of acute caerulein pancreatitis is sufficient to accelerate the development of cystic lesions in KPN+/- mice. Epithelial cells of cystic lesions of KPN+/- mice express MUC1, MUC5AC, and MUC6, but lack expression of MUC2, CDX2, and acinar markers, indicative of a pancreato-biliary/gastric phenotype. In accordance with this, in human samples we found a non-significantly decreased expression of NR5A2 in mucinous tumours, compared with conventional PDAC. These results highlight that the effects of loss of one Nr5a2 allele are time- and cell context-dependent. KPN+/- mice represent a new model to study the formation of cystic pancreatic lesions and their relationship with PanINs and classical PDAC. Our findings suggest that pancreatitis could also contribute to acceleration of cystic tumour progression in patients. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
- **A Critical Assessment of Postneoadjuvant Therapy Pancreatic Cancer Regression Grading Schemes With a Proposal for a Novel Approach**
The American journal of surgical pathology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33074853
Currently, there is no consensus on the optimal tumor response score (TRS) system to assess regression in pancreatic cancers resected after neoadjuvant therapy. We developed a novel TRS (Royal North Shore [RNS] system) based on estimating the percentage of tumor bed occupied by viable cancer and categorized into 3 tiers: grade 1 (≤10%), grade 2 (11% to 75%), and grade 3 (>75%). We assessed 147 resected carcinomas with this and other TRS systems (College of American Pathologists [CAP], MD Anderson Cancer Center [MDACC], and Evans). The 3-tiered RNS system predicted median survival after surgery for grades 1, 2, and 3 of 54, 23, and 9 months, respectively (P<0.05). The CAP, MDACC, and Evans systems also predicted survival (P<0.05) but less consistently. The median survival for MDACC and CAP grade 0 (complete regression) was less than MDACC grade 1 and CAP grades 1 and 2. There was no difference in survival between CAP grades 2 and 3 (P=0.960), Evans grades 1 and 2a (P=0.395), and Evans grades 2a and 2b (P=0.587). Interobserver concordance was weak for CAP (κ=0.431), moderate for MDACC (κ=0.691), minimal for Evans (κ=0.307), and moderate to strong for RNS (κ=0.632 to 0.84). Of age, sex, size, stage, grade, perineural and vascular invasion, extrapancreatic extension, margin status, and RNS score, only RNS score, vascular invasion, and extrapancreatic extension predicted survival in univariate analysis. Only extrapancreatic extension (P=0.034) and RNS score (P<0.0001) remained significant in multivariate analysis. We conclude that the RNS system is a reproducible and powerful predictor of survival after resection for pancreatic cancers treated with neoadjuvant therapy and should be investigated in larger cohorts.
- **Hyalinized stroma is a characteristic feature of pancreatic intraductal oncocytic papillary neoplasm: An immunohistochemical study**
Annals of diagnostic pathology 2020 Oct;49():151639
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33069084
Hyalinized stroma (HS) is a dense, eosinophilic, and amorphous extracellular material in the stroma. HS is observed in several tumors; however, it has not been comprehensively studied in pancreatic intraductal papillary mucinous neoplasm (IPMN) or intraductal oncocytic papillary neoplasm (IOPN). Here, we aimed to evaluate the immunohistochemical and microscopic characteristics of HS in IPMN and IOPN. The prevalence of HS was determined in 168 cases of IPMN, including intestinal type (IPMN-I), gastric type (IPMN-G), and pancreatobiliary type (IPMN-PB), as well as in 11 cases of IOPN. Immunohistochemical staining for laminin and collagen (types I, II, III, IV, and V), as well as Congo red staining were performed in IPMN and IOPN cases containing HS. The prevalence of HS among the IPMN and IOPN specimens was 1.2% (2/168 cases) and 45.5% (5/11 cases), respectively. The prevalence rates of HS in each IPMN subtype were as follows: 2.2% (2/91 cases) in IPMN-G, and 0% in IPMN-PB and IPMN-I. All seven HS cases were positive for collagen I, III, IV, and V but were negative for Congo red staining. Most cases showed negative, focal, or weak expression of laminin and type II collagen. These findings indicate that HS is associated with IOPN and is primarily composed of collagen fibers.
- **The use of immunohistochemistry for IgG4 in the diagnosis of autoimmune pancreatitis: A systematic review and meta-analysis**
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.] 2020 Dec;20(8):1611-1619
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33060017
BACKGROUND: The diagnosis of autoimmune pancreatitis (AIP) remains challenging, especially when serum IgG4 is normal or imaging features are indeterminate. We performed a systematic review and meta-analysis to evaluate the performance of IgG4 immunostaining of pancreatic, biliary, and ampullary tissues as a diagnostic aid for AIP. METHODS: A comprehensive literature search of the PubMed, EMBASE, and Ovid MEDLINE databases was conducted until February 2020. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies checklist. A random-effects model was used to summarize the diagnostic odds ratio and other measures of accuracy. RESULTS: The meta-analysis included 20 studies comprising 346 patients with AIP and 590 patients with other pancreatobiliary diseases, including 371 pancreatobiliary malignancies. The summary estimates for tissue IgG4 in discriminating AIP and controls were as follows: diagnostic odds ratio 38.86 (95% confidence interval (CI), 18.70-80.75); sensitivity 0.64 (95% CI, 0.59-0.69); specificity 0.93 (95% CI, 0.91-0.95). The area under the curve was 0.939 for tissue IgG4 in discriminating AIP and controls. Subgroup analysis revealed no significant difference in diagnostic accuracy according to control groups (pancreatobiliary cancer versus other chronic pancreatitis) and sampling site (pancreas versus bile duct/ampulla). CONCLUSIONS: Current data demonstrate that IgG4 immunostaining of pancreatic, biliary, and ampullary tissue has a high specificity but moderate sensitivity for diagnosing AIP. IgG4 immunostaining may be useful in supporting a diagnosis of AIP when AIP is clinically suspected, but a combination of imaging and serology does not provide a conclusive diagnosis.
- **Expression of the EWSR1-FLI1 fusion oncogene in pancreas cells drives pancreatic atrophy and lipomatosis**
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.] 2020 Dec;20(8):1673-1681
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33051146
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) harbors mutant KRAS as the most common driver mutation. Studies on mouse models have uncovered the tumorigenic characteristics of the Kras oncogene driving pancreatic carcinogenesis. Similarly, Ewing sarcoma predominantly depends on the occurrence of the EWSR1-FLI1 fusion oncogene. The expression of EWSR1-FLI1 affects pro-tumorigenic pathways and induces cell transformation. In this study, we investigated whether mutant Kras could be exchanged by another potent oncogene, such as EWSR1-FLI1, to initiate pancreatic cancer development. METHODS: We generated two conditional mouse models expressing mutant KrasG12D (KC) or the EWSR1-FLI1 oncogene (E/F) in pancreas cells. Pancreatic tissue was collected from the mice at 4-6 weeks and 11-13 weeks of age as well as from survival cohorts to determine the development of spontaneous acinar-to-ductal metaplasia (ADM) and neoplastic lesions. Immunohistochemistry and immunofluorescence staining were performed to characterize and quantify changes in tissue morphology. RESULTS: The expression of the EWSR1-FLI1 fusion protein in pancreas cells was confirmed by positive FLI1 immunohistochemistry staining. Notably, the EWSR1-FLI1 expression in pancreas cells resulted in a strong depletion of the acinar cell mass and an extensive lipomatosis. Although the E/F mice exhibited spontaneous ADM formation and a shorter overall survival rate compared to KC mice, no development of neoplastic lesion was observed in aging E/F mice. CONCLUSIONS: The expression of the EWSR1-FLI1 oncogene leads to a strong pancreatic atrophy and lipomatosis. ADM formation indicates that pancreatic acinar cells are susceptible for EWSR1-FLI1-mediated oncogenic transformation to a limited extent. However, the EWSR1-FLI1 oncogene is insufficient to induce pancreatic cancer development.
- **Three distinct stroma types in human pancreatic cancer identified by image analysis of fibroblast subpopulations and collagen**
Clinical cancer research : an official journal of the American Association for Cancer Research 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33046515
PURPOSE: Cancer-associated fibroblasts have emerged to be highly heterogenous and can play multifaced roles in dictating pancreatic ductal adenocarcinoma (PDAC) progression, immunosuppression and therapeutic response, highlighting the need for a deeper understanding of stromal heterogeneity between patients and even within a single tumor. We hypothesized that image analysis of fibroblast subpopulations and collagen in PDAC tissues might guide stroma-based patient stratification to predict clinical outcomes and tumor characteristics. EXPERIMENTAL DESIGN: A novel multiplex immunohistochemistry-based image analysis system was established to digitally differentiate fibroblast subpopulations. Using whole-tissue slides from 215 treatment-naïve PDACs, we performed concurrent quantification of principal fibroblast subpopulations and collagen and defined three stroma types: collagen-rich stroma, fibroblast activation protein a (FAP)-dominant fibroblast-rich stroma and a smooth muscle actin (ACTA2)-dominant fibroblast-rich stroma. These stroma types were assessed for the associations with cancer-specific survival by multivariable Cox regression analyses, and with clinicopathological factors including CD8+ cell density. RESULTS: FAP-dominant fibroblasts and ACTA2-dominant fibroblasts represented the principal distinct fibroblast subpopulations in tumor stroma. Stroma types were associated with patient survival, SMAD4 status and transcriptome signatures. Compared with FAP-dominant fibroblast-rich stroma, collagen-rich stroma correlated with prolonged survival (HR, 0.57; 95% CI, 0.33-0.99), while ACTA2-dominant fibroblast-rich stroma exhibited poorer prognosis (HR, 1.65; 95% CI, 1.06-2.58). FAP-dominant fibroblast-rich stroma was additionally characterized by restricted CD8+-cell infiltrates and intense neutrophil infiltration. CONCLUSIONS: This study identified three distinct stroma types differentially associated with survival, immunity and molecular features, thereby underscoring the importance of stromal heterogeneity in subtyping pancreatic cancers and supporting the development of anti-stromal therapies.
- **Amsterdam International Consensus Meeting: tumor response scoring in the pathology assessment of resected pancreatic cancer after neoadjuvant therapy**
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33041332
Histopathologically scoring the response of pancreatic ductal adenocarcinoma (PDAC) to neoadjuvant treatment can guide the selection of adjuvant therapy and improve prognostic stratification. However, several tumor response scoring (TRS) systems exist, and consensus is lacking as to which system represents best practice. An international consensus meeting on TRS took place in November 2019 in Amsterdam, The Netherlands. Here, we provide an overview of the outcomes and consensus statements that originated from this meeting. Consensus (≥80% agreement) was reached on a total of seven statements: (1) TRS is important because it provides information about the effect of neoadjuvant treatment that is not provided by other histopathology-based descriptors. (2) TRS for resected PDAC following neoadjuvant therapy should assess residual (viable) tumor burden instead of tumor regression. (3) The CAP scoring system is considered the most adequate scoring system to date because it is based on the presence and amount of residual cancer cells instead of tumor regression. (4) The defining criteria of the categories in the CAP scoring system should be improved by replacing subjective terms including "minimal" or "extensive" with objective criteria to evaluate the extent of viable tumor. (5) The improved, consensus-based system should be validated retrospectively and prospectively. (6) Prospective studies should determine the extent of tissue sampling that is required to ensure adequate assessment of the residual cancer burden, taking into account the heterogeneity of tumor response. (7) In future scientific publications, the extent of tissue sampling should be described in detail in the "Materials and methods" section.
- **Establishing a living biobank of patient-derived organoids of intraductal papillary mucinous neoplasms of the pancreas**
Laboratory investigation; a journal of technical methods and pathology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33037322
Pancreatic cancer (PaCa) is the third leading cause of cancer-related deaths in the United States. There is an unmet need to develop strategies to detect PaCa at an early, operable stage and prevent its progression. Intraductal papillary mucinous neoplasms (IPMNs) are cystic PaCa precursors that comprise nearly 50% of pancreatic cysts detected incidentally via cross-sectional imaging. Since IPMNs can progress from low- and moderate-grade dysplasia to high-grade dysplasia and invasion, the study of these lesions offers a prime opportunity to develop early detection and prevention strategies. Organoids are an ideal preclinical platform to study IPMNs, and the objective of the current investigation was to establish a living biobank of patient-derived organoids (PDO) from IPMNs. IPMN tumors and adjacent normal pancreatic tissues were successfully harvested from 15 patients with IPMNs undergoing pancreatic surgical resection at Moffitt Cancer Center & Research Institute (Tampa, FL) between May of 2017 and March of 2019. Organoid cultures were also generated from cryopreserved tissues. Organoid count and size were determined over time by both Image-Pro Premier 3D Version 9.1 digital platform and Matlab application of a Circular Hough Transform algorithm, and histologic and genomic characterization of a subset of the organoids was performed using immunohistochemistry and targeted sequencing, respectively. The success rates for organoid generation from IPMN tumor and adjacent normal pancreatic tissues were 81% and 87%, respectively. IPMN organoids derived from different epithelial subtypes showed different morphologies in vitro, and organoids recapitulated histologic and genomic characteristics of the parental IPMN tumor. In summary, this preclinical model has the potential to provide new opportunities to unveil mechanisms of IPMN progression to invasion and to shed insight into novel biomarkers for early detection and targets for chemoprevention.
- **Multiregion whole-exome sequencing of intraductal papillary mucinous neoplasms reveals frequent somatic KLF4 mutations predominantly in low-grade regions**
Gut 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33028669
OBJECTIVE: Intraductal papillary mucinous neoplasms (IPMNs) are non-invasive precursor lesions that can progress to invasive pancreatic cancer and are classified as low-grade or high-grade based on the morphology of the neoplastic epithelium. We aimed to compare genetic alterations in low-grade and high-grade regions of the same IPMN in order to identify molecular alterations underlying neoplastic progression. DESIGN: We performed multiregion whole exome sequencing on tissue samples from 17 IPMNs with both low-grade and high-grade dysplasia (76 IPMN regions, including 49 from low-grade dysplasia and 27 from high-grade dysplasia). We reconstructed the phylogeny for each case, and we assessed mutations in a novel driver gene in an independent cohort of 63 IPMN cyst fluid samples. RESULTS: Our multiregion whole exome sequencing identified KLF4, a previously unreported genetic driver of IPMN tumorigenesis, with hotspot mutations in one of two codons identified in >50% of the analyzed IPMNs. Mutations in KLF4 were significantly more prevalent in low-grade regions in our sequenced cases. Phylogenetic analyses of whole exome sequencing data demonstrated diverse patterns of IPMN initiation and progression. Hotspot mutations in KLF4 were also identified in an independent cohort of IPMN cyst fluid samples, again with a significantly higher prevalence in low-grade IPMNs. CONCLUSION: Hotspot mutations in KLF4 occur at high prevalence in IPMNs. Unique among pancreatic driver genes, KLF4 mutations are enriched in low-grade IPMNs. These data highlight distinct molecular features of low-grade and high-grade dysplasia and suggest diverse pathways to high-grade dysplasia via the IPMN pathway.
- **Effect of Germline Mutations in Homologous Recombination Repair Genes on Overall Survival of Patients with Pancreatic Adenocarcinoma**
Clinical cancer research : an official journal of the American Association for Cancer Research 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33028596
PURPOSE: To compare the clinical characteristics and overall survival (OS) of germline mutation carriers in homologous recombination repair (HRR) genes and noncarriers with pancreatic ductal adenocarcinoma (PDAC). METHODS: Germline DNA from 3,078 patients with PDAC enrolled in a prospective registry at Mayo Clinic between 2000 and 2017 was analyzed for mutations in 37 cancer predisposition genes. Characteristics and OS of patients with mutations in eight genes (ATM, BARD1, BRCA1, BRCA2, BRIP1, PALB2, RAD51C, and RAD51D) involved in HRR were compared with patients testing negative for mutations in all 37 genes. RESULTS: The 175 HRR mutation carriers and 2,730 noncarriers in the study had a median duration of follow-up of 9.9 years. HRR mutation carriers were younger (median age at diagnosis: 63 vs. 66 years, P < 0.001) and more likely to have metastatic disease at diagnosis (46% vs. 36%, P = 0.004). In a multivariable model adjusting for sex, age at diagnosis, and tumor staging, patients with germline HRR mutations had a significantly longer OS compared with noncarriers [HR, 0.83; 95% confidence interval (CI), 0.70-0.97; P = 0.02]. Further gene-level analysis demonstrated that germline ATM mutation carriers had longer OS compared with patients without germline mutations in any of the 37 genes (HR, 0.72; 95% CI, 0.55-0.94; P = 0.01). CONCLUSIONS: This study demonstrates that germline mutation carrier status in PDAC is associated with longer OS compared with noncarriers. Further research into tumor biology and response to platinum-based chemotherapy in germline mutation carriers with PDAC are needed to better understand the association with longer OS.
- **Kras mutation rate precisely orchestrates ductal derived pancreatic intraepithelial neoplasia and pancreatic cancer**
Laboratory investigation; a journal of technical methods and pathology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33009500
Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death in the United States. Despite the high prevalence of Kras mutations in pancreatic cancer patients, murine models expressing the oncogenic mutant Kras (Krasmut) in mature pancreatic cells develop PDAC at a low frequency. Independent of cell of origin, a second genetic hit (loss of tumor suppressor TP53 or PTEN) is important for development of PDAC in mice. We hypothesized ectopic expression and elevated levels of oncogenic mutant Kras would promote PanIN arising in pancreatic ducts. To test our hypothesis, the significance of elevating levels of K-Ras and Ras activity has been explored by expression of a CAG driven LGSL-KrasG12V allele (cKras) in pancreatic ducts, which promotes ectopic Kras expression. We predicted expression of cKras in pancreatic ducts would generate neoplasia and PDAC. To test our hypothesis, we employed tamoxifen dependent CreERT2 mediated recombination. Hnf1b:CreERT2;KrasG12V (cKrasHnf1b/+) mice received 1 (Low), 5 (Mod) or 10 (High) mg per 20 g body weight to recombine cKras in low (cKrasLow), moderate (cKrasMod), and high (cKrasHigh) percentages of pancreatic ducts. Our histologic analysis revealed poorly differentiated aggressive tumors in cKrasHigh mice. cKrasMod mice had grades of Pancreatic Intraepithelial Neoplasia (PanIN), recapitulating early and advanced PanIN observed in human PDAC. Proteomics analysis revealed significant differences in PTEN/AKT and MAPK pathways between wild type, cKrasLow, cKrasMod, and cKrasHigh mice. In conclusion, in this study, we provide evidence that ectopic expression of oncogenic mutant K-Ras in pancreatic ducts generates early and late PanIN as well as PDAC. This Ras rheostat model provides evidence that AKT signaling is an important early driver of invasive ductal derived PDAC.
- **Evidence of a common cell origin in a case of pancreatic mixed intraductal papillary mucinous neoplasm-neuroendocrine tumor**
Virchows Archiv : an international journal of pathology 2020 Oct;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33005981
Recently, the term mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) has been proposed as an umbrella definition covering different possible combinations of mixed neuroendocrine-exocrine neoplasms. Among these, the adenoma plus neuroendocrine tumor (NET) combination is among the rarest and not formally recognized by the 2019 WHO Classification. In this setting, the debate between either collision tumors or true mixed neoplasms is still unsolved. In this report, a pancreatic intraductal papillary mucinous neoplasm (IPMN) plus a NET is described, and the molecular investigations showed the presence in both populations of the same KRAS, GNAS, and CDKN2A mutations and the amplification of the CCND1 gene. These data prove clonality and support a common origin of both components, therefore confirming the true mixed nature. For this reason, mixed neuroendocrine-exocrine neoplasms, in which the exocrine component is represented by a glandular precursor lesion (adenoma/IPMN) only, should be included into the MiNEN family.
- **GLUT-1 as a predictor of worse prognosis in pancreatic adenocarcinoma: immunohistochemistry study showing the correlation between expression and survival**
BMC cancer 2020 Sep;20(1):909
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32967636
BACKGROUND: Various parameters have been considered for predicting survival in pancreatic ductal adenocarcinoma. Information about western population is missing. The aim of this study is to assess the association between Glucose transporter type 1 (GLUT-1) expression and prognosis for patients with PDAC submitted for surgical resection in a European cohort. METHODS: Retrospective analysis of PDAC specimens after pancreatoduodenectomy assessing GLUT-1 expression according to intensity (weak vs strong) and extension (low if < 80% cells were stained, high if > 80%) was performed. Statistical analysis was performed using the exact Fisher test, Student t test or the Mann-Whitney U test. Survival was analysed using the Kaplan-Meier method and compared with the Log-rank test. The differences were considered significant at a two-sided p value of < 0.05. All statistical analyses were performed using SPSS® 23.0 for Windows (SPSS Inc., Chicago, IL, USA). RESULTS: Our study consisted of 39 patients of which 58.9% presented with weak and 41.1% with strong intensity. The median extension was 90%: 28.2% cases presented with a low extension and 71.8% with a high extension. No significant differences related to intensity were found. The high-extension group showed a higher percentage of T3 PDAC (92.9% vs 63.6%, p = 0.042) and LNR20 (35.7% vs 0%, p = 0.037) as well as shorter disease-free survival (17.58 vs 54.46 months; p = 0.048). CONCLUSIONS: Our findings suggest that GLUT-1 could be related to higher aggressivity in PDAC and could be used as a prognostic marker, identifying patients with a worse response to current therapies who could benefit from more aggressive treatments.
- **Comprehensive histological evaluation with clinical analysis of venous invasion in pancreatic ductal adenocarcinoma: From histology to clinical implications**
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... [et al.] 2020 Oct;20(7):1486-1494
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32948429
OBJECTIVES: Venous invasion is a poor prognostic factor for pancreatic ductal adenocarcinoma (PDAC). However, our understanding of various features of venous invasion is limited. Our aim is to comprehensively evaluate various histopathologic features of venous invasion, including status, type (lymphatic or venous), number of invasion foci, and histologic pattern (pancreatic intraepithelial neoplasia [PanIN]-like, conventional) in PDACs. METHODS: Various features of venous invasion, including status, number of invasion foci, histologic patterns [pancreatic intraepithelial neoplasia (PanIN)-like, conventional], and size of involved vessels in 471 surgically resected PDACs were evaluated with all available hematoxylin and eosin (H&E)-stained slides. RESULTS: Venous invasion was observed in 319 cases (67.7%) and was more frequently associated with increased tumor size, extrapancreatic extension, resection margin involvement, diffuse tumor distribution, lymph node metastasis, and perineural invasion (all Ps < .05). High frequency (≥3 foci) of venous invasion was associated with shorter overall survival both in the entire group and in the early stage subgroup (stage I; all Ps < .05). Multivariate analysis indicated that a high frequency (≥3 foci) of venous invasion, large tumor size (>4 cm), higher histologic grade, and lymph node metastasis, were independent prognostic factors of worse overall survival (all Ps < .05). CONCLUSION: Precise evaluation of venous invasion status, including foci number of invasion, can provide additional prognostic information for patients undergoing surgical resection of PDAC, especially for those with early disease stage.
- **Positivity for SATB2 distinguishes Islet1 positive rectal neuroendocrine tumours from pancreaticoduodenal neuroendocrine tumours**
Journal of clinical pathology 2020 Sep;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32934105
AIMS: Determining the site of origin of a metastatic neuroendocrine tumour (NET) can be challenging and has important prognostic and therapeutic implications. An immunohistochemical (IHC) panel consisting of TTF1, CDX2, PAX8/PAX6 and Islet1 is often employed. However, there can be a significant IHC overlap among different primary sites. Herein, we sought to determine the utility of including Special AT-rich sequence binding protein-2 (SATB2) in the IHC panel that is used for determining the site of origin of a metastatic NET. METHODS: Paraffin tissue microarrays consisting of 137 primary NETs (26 lung, 22 jejunoileal, 8 appendix, 5 stomach, 4 duodenum, 17 rectum and 55 pancreas) were stained for SATB2, in addition to the well-described lineage-associated markers, such as TTF1, CDX2, PAX6 and Islet1. Additionally, a tissue microarray consisting of 21 metastatic NETs (1 lung, 1 stomach, 8 jejunoileal and 11 pancreas) was stained for TTF1, CDX2, SATB2 and Islet1. The results were recorded as no staining, weak staining and moderate to strong staining. RESULTS: All appendiceal NETs and majority (88%) of the rectal NETs were positive for SATB2. All primary foregut NETs (stomach, pancreas, duodenum and lung) were negative for SATB2, except for one pulmonary NET with weak staining. However, among the metastatic tumours, 5 of 11 pancreatic NETs, 1 stomach NET, 1 lung NET and 2 of 8 jejunoileal NETs showed weak staining. Receiver operating characteristic analysis incorporating sensitivity and specificity data of IHC panel, considering moderate to strong staining as truly positive cases, showed that inclusion of SATB2 to the previously described NET IHC panel outperformed the panel without SATB2, raising the specificity for pancreaticoduodenal NETs from 81.2% to 100%, with a positive predictive value (PPV) of 100% and negative predictive value (NPV) of 82.22% (p<0.0001); for appendiceal NETs the specificity changed from 99.1% to 98.5% and sensitivity increased from 11.8% to 80%, with a PPV and NPV of 66.67% and 99.26%, respectively (p<0.0001); and for rectal NETs the specificity increased from 97.6% to 99.3% and sensitivity raised from 7.1% to 66.7%, with a PPV and NPV of 80% and 98.53%, respectively (p<0.0001). CONCLUSIONS: SATB2 stain is useful in differentiatingIslet1/PAX6 positive pancreatic and rectal NETs, as rectal NETs are typically moderately to strongly positive for SATB2 and pancreatic NETs are usually negative or weakly positive for SATB2. Moderate to strong staining for SATB2 is suggestive of an appendiceal or a rectal primary. SATB2 may complement the panel of CDX2, TTF1 and Islet1 in determining the site of origin of an NET in a metastatic setting.
- **Clinical and genomic characterisation of mismatch repair deficient pancreatic adenocarcinoma**
Gut 2020 Sep;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32933947
OBJECTIVE: To describe the clinical, pathological and genomic characteristics of pancreatic cancer with DNA mismatch repair deficiency (MMRD) and proficiency (MMRP). DESIGN: We identified patients with MMRD and MMRP pancreatic cancer in a clinical cohort (N=1213, 519 with genetic testing, 53 with immunohistochemistry (IHC)) and a genomic cohort (N=288 with whole-genome sequencing (WGS)). RESULTS: 12 out of 1213 (1.0%) in the clinical cohort were MMRD by IHC or WGS. Of the 14 patients with Lynch syndrome, 3 (21.4%) had an MMRP pancreatic cancer by IHC, and 4 (28.6%) were excluded because tissue was unavailable for testing. MMRD cancers had longer overall survival after surgery (weighted HR after coarsened exact matching 0.11, 95% CI 0.02 to 0.78, p=0.001). One patient with an unresectable MMRD cancer has an ongoing partial response 3 years after starting treatment with PD-L1/CTLA-4 inhibition. This tumour showed none of the classical histopathological features of MMRD. 9 out of 288 (3.1%) tumours with WGS were MMRD. Despite markedly higher tumour mutational burden and neoantigen loads, MMRD cancers were significantly less likely to have mutations in usual pancreatic cancer driver genes like KRAS and SMAD4, but more likely to have mutations in genes that drive cancers with microsatellite instability like ACV2RA and JAK1. MMRD tumours were significantly more likely to have a basal-like transcriptional programme and elevated transcriptional markers of immunogenicity. CONCLUSIONS: MMRD pancreatic cancers have distinct clinical, pathological and genomic profiles. Patients with MMRD pancreatic cancer should be considered for basket trials targeting enhanced immunogenicity or the unique genomic drivers in these malignancies.
- **SMAD4-Expressing Pancreatic Ductal Adenocarcinomas Have Better Response to Neoadjuvant Therapy and Significantly Lower Lymph Node Metastasis Rates**
Pancreas 2020 10;49(9):1153-1160
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32897998
OBJECTIVE: For many patients whose pancreatic ductal adenocarcinoma (PDAC) is locally advanced, neoadjuvant therapy has been proposed as a way to decrease tumor burden. Pancreatic ductal adenocarcinoma is generally thought to be resistant to chemotherapy and radiation, however, response to neoadjuvant therapy in PDAC has been described in a subset of patients. The SMAD4 status is considered to be an important molecular feature which distinguishes two subsets of PDAC, SMAD4-positive and -negative tumors. The objective of this study was to evaluate the neoadjuvant treatment response rate as well as compare the different clinicopathologic variables between SMAD4-positive and -negative tumors. METHODS: We analyzed the data of patients who underwent surgical resection for PDAC from 2009-2019. Our cohort from a single institution included 233 patients. RESULTS: Of the 233 cases, 143 (61.4%) were SMAD4-negative and 90 (38.6%) were SMAD4-positive. Overall, SMAD4-positive tumors with neoadjuvant therapy had better treatment response and better tumor regression scores. In addition, SMAD4-positive tumors had a significantly lower lymph node metastasis rate in both the neoadjuvant and nonneoadjuvant setting. CONCLUSIONS: Further characterization of the role of SMAD4 within the context of neoadjuvant therapy will lead to improved personalized therapeutic strategies.
- **Clinical Routine Application of the Second-generation Neuroendocrine Markers ISL1, INSM1, and Secretagogin in Neuroendocrine Neoplasia: Staining Outcomes and Potential Clues for Determining Tumor Origin**
Endocrine pathology 2020 Dec;31(4):401-410
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32813226
Neuroendocrine neoplasms (NENs) have traditionally been identified via expression of proteins associated to the regulation of secretory vesicles and granules. We report the clinical usage of the "second-generation" proteins ISL LIM homeobox 1 (ISL1), INSM transcriptional repressor 1 (INSM1), and secretagogin (SECG) as immunohistochemical markers of neuroendocrine differentiation since their introduction in clinical routine and compare the results with the established proteins chromogranin A (CGA) and synaptophysin (SYP). In total, 161 tumors, including 139 NENs and 22 "non-NENs" (unrelated tumors with an initial suspicion of NEN), were informatively stained for ISL1, and subsets were also interrogated for INSM1 and/or SECG. Diffuse or focal positive immunoreactivity was noted for ISL1 in 91/139 NENs (65%) and in 6/22 (27%) non-NENs, for INSM1 in 76/85 NENs (89%) and in 2/5 (40%) non-NENs, and for SECG in 49 out of 64 NENs (77%) and in 0/5 non-NENs (0%). Generally, ISL1, INSM1, and SECG exhibited sensitivities in line with or slightly below that of CGA and SYP-largely attributable to tissue-specific patterns regarding tumoral origin. Moreover, for pancreatic and small intestinal NENs, the two largest subgroups, ISL1 staining results were consistent irrespectively of tumor source and WHO grade. We verify previously suggested immunohistochemical schemes of neuroendocrine markers of first- and second-generations to facilitate the diagnostic process for NENs and confirm that the second-generation neuroendocrine markers display tissue-specific patterns. We therefore recommend their implementation in tertiary endocrine pathology centers, not least to aid in the identification of primary tumors when analyzing metastases.
- **Intraductal pancreatic cancer is less responsive than cancer in the stroma to neoadjuvant chemotherapy**
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2020 10;33(10):2026-2034
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32457408
Neoadjuvant chemotherapy (NAC) is often the treatment of choice for borderline resectable and locally advanced invasive pancreatic ductal adenocarcinoma (PDAC); however, most cancers only partially respond to therapy. We hypothesized that the location of residual neoplastic cells in resected specimens following NAC could provide a clue as to the mechanisms of resistance. PDAC cells invade the stroma but can also invade back into and spread via the pancreatic ducts, which has been referred to as "cancerization of ducts" (COD). We compared the responsiveness to chemotherapy between PDAC cells in the stroma and PDAC cells in the duct. Pancreatic resections from a total of 174 PDAC patients (NAC, n = 97; immediate surgery, n = 77) were reviewed. On hematoxylin and eosin sections, COD was identified at the same prevalence in both groups (NAC: 50/97 cases, 52%; immediate surgery: 39/77 cases, 51%; p = 0.879, Fisher's exact test). However, using quantitative image analysis of CK19 immunohistochemistry, we found that the proportion of cancer cells that were intraductal was significantly different between the NAC and immediate surgery groups (median; 12.7% vs. 1.99%, p < 0.0001, Mann-Whitney U test). This proportion was highest in patients with marked therapy responses (36.2%) compared with patients with moderate or poor responses (7.21 & 7.91%). In summary, our data suggest that intraductal components in PDAC are less responsive to chemotherapy than the remainder of the tumor, which could have important implications for therapeutic resistance.
- **Negative prognostic impact of PD-L1 expression in tumor cells of undifferentiated (anaplastic) carcinoma with osteoclast-like giant cells of the pancreas: study of 13 cases comparing ductal pancreatic carcinoma and review of the literature**
Virchows Archiv : an international journal of pathology 2020 Nov;477(5):687-696
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32424767
Pancreatic carcinoma remains one of the leading cancer-related causes of death worldwide and is generally characterized by a dismal prognosis and limited potential for oncologic treatment. A rare subvariant of pancreatic cancer, undifferentiated carcinoma with osteoclast-like giant cells (UCOGC), has an unpredictable prognosis according to many previous studies, with unexpectedly long survival in individual cases. In this study, we collected, retrospectively, 13 cases of well-documented UCOGCs and performed immunohistochemistry focused on the expression of the programmed death-ligand 1 (PD-L1) and several other potential therapeutic and predictive markers (PanTRK, p53, MSH2, PMS2, and the number of tumor-infiltrating lymphocytes), to explore their correlation with the follow-up of the patients. As a control group, we examined 24 cases of conventional pancreatic ductal adenocarcinoma (PDAC). In our results, PanTRK was negative in all 24 cases. P53 did not show any significant differences between UCOGCs and PDACs, and the entire cohort was MSH2, MLH1, PMS2, and MSH6 positive. Significant differences were present in the analysis of PD-L1: UCOGCs were found to express PD-L1 significantly more frequently and have a higher number of tumor-infiltrating lymphocytes than PDAC. The expression of PD-L1 was related to significantly shorter survival in patients with UCOGC and in the entire cohort. Patients with PD-L1 negative UCOGCs displayed surprisingly long survival in comparison to PD-L1 positive UCOGCs and PDACs (both PD-L1+ and PD-L1-). We compared our results with previously published data, and, after statistical analysis, we were able to identify PD-L1 as an effective prognostic marker of UCOGC and suggest a strong need for a clinical trial of immune checkpoint immunotherapy in patients with advanced PD-L1 positive UCOGC.
- **RAF1 rearrangements are common in pancreatic acinar cell carcinomas**
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2020 09;33(9):1811-1821
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32358589
There is now evidence that gene fusions activating the MAPK pathway are relatively common in pancreatic acinar cell carcinoma with potentially actionable BRAF or RET fusions being found in ~30%. We sought to investigate the incidence of RAF1 fusions in pancreatic malignancies with acinar cell differentiation. FISH testing for RAF1 was undertaken on 30 tumors comprising 25 'pure' acinar cell carcinomas, 2 mixed pancreatic acinar-neuroendocrine carcinomas, 1 mixed acinar cell-low grade neuroendocrine tumor and 2 pancreatoblastomas. RAF1 rearrangements were identified in 5 cases and confirmed by DNA and RNA sequencing to represent oncogenic fusions (GATM-RAF1, GOLGA4-RAF1, PDZRN3-RAF1, HERPUD1-RAF1 and TRIM33-RAF1) and to be mutually exclusive with BRAF and RET fusions, as well as KRAS mutations. Large genome-wide copy number changes were common and included 1q gain and/or 1p loss in all five RAF1 FISH-positive acinar cell carcinomas. RAF1 expression by immunohistochemistry was found in 3 of 5 (60%) of fusion-positive cases and no FISH-negative cases. Phospho-ERK1/2 expression was found in 4 of 5 RAF1-fusion-positive cases. Expression of both RAF1 and phospho-ERK1/2 was heterogeneous and often only detected at the tumor-stroma interface, thus limiting their clinical utility. We conclude that RAF1 gene rearrangements are relatively common in pancreatic acinar cell carcinomas (14.3% to 18.5% of cases) and can be effectively identified by FISH with follow up molecular testing. The combined results of several studies now indicate that BRAF, RET or RAF1 fusions occur in between one third and one-half of these tumors but are extremely rare in other pancreatic malignancies. As these fusions are potentially actionable with currently available therapies, a strong argument can be made to perform FISH or molecular testing on all pancreatic acinar cell carcinomas.
- **Genetic and clinical correlates of entosis in pancreatic ductal adenocarcinoma**
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2020 09;33(9):1822-1831
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32350415
Entosis is a type of regulated cell death that promotes cancer cell competition. Though several studies have revealed the molecular mechanisms that govern entosis, the clinical and genetic correlates of entosis in human tumors is less well understood. Here we reviewed entotic cell-in-cell (CIC) patterns in a large single institution sequencing cohort (MSK IMPACT clinical sequencing cohort) of more than 1600 human pancreatic ductal adenocarcinoma (PDAC) samples to identify the genetic and clinical correlates of this cellular feature. After case selection, 516 conventional PDACs and 21 ASCs entered this study and ~45,000 HPFs (median 80 HPFs per sample) were reviewed; 549 entotic-CICs were detected through our cohort. We observed that entotic-CIC occurred more frequently in liver metastasis compared with primary in PDAC. Moreover, poorly differentiated adenocarcinoma or adenosquamous carcinoma had more entotic-CIC than well or moderately differentiated adenocarcinoma. With respect to genetic features TP53 mutations, KRAS amplification, and MYC amplification were significantly associated with entosis in PDAC tissues. From a clinical standpoint entotic CICs were independently associated with a poor prognosis by multivariate Cox regression analysis when considering all cases or primary PDACs specifically. These results provide a contextual basis for understanding entosis in PDAC, a highly aggressive cancer for which molecular insights are needed to improve survival.
- **Does Site Matter? Impact of Tumor Location on Pathologic Characteristics, Recurrence, and Survival of Resected Pancreatic Ductal Adenocarcinoma**
Annals of surgical oncology 2020 Oct;27(10):3898-3912
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32307617
BACKGROUND: The authors hypothesized that in resected pancreatic adenocarcinoma (PDAC), pathologic characteristics, oncologic outcomes, prognostic factors, and the accuracy of the American Joint Committee on Cancer (AJCC) staging system might differ based on tumor location. METHODS: Patients undergoing pancreatectomy for PDAC at two academic institutions from 2000 to 2015 were retrieved. A comparative analysis between head (H-PDAC) and body-tail (BT-PDAC) tumors was performed using uni- and multivariable models. The accuracy of the eighth AJCC staging system was analyzed using C-statistics. RESULTS: Among 1466 patients, 264 (18%) had BT-PDAC, which displayed greater tumor size but significantly lower rates of perineural invasion and G3/4 grading. Furthermore, BT-PDAC was associated with a lower frequency of nodal involvement and a greater representation of earlier stages. The recurrence-free survival and disease-specific survival times were longer for BT-PDAC (16 vs 14 months [p = 0.020] and 33 vs 26 months [p = 0.026], respectively), but tumor location was not an independent predictor of recurrence or survival in the multivariable analyses. The recurrence patterns did not differ. Certain prognostic factors (i.e., CA 19.9, grading, R-status, and adjuvant treatment) were common, whereas others were site-specific (i.e., preoperative pain, diabetes, and multivisceral resection). The performances of the AJCC staging system were similar (C-statistics of 0.573 for H-PDAC and 0.597 for BT-PDAC, respectively). CONCLUSIONS: Despite differences in pathologic profile found to be in favor of BT-PDAC, tumor location was not an independent predictor of recurrence or survival after pancreatectomy. An array of site-specific prognostic factors was identified, but the AJCC staging system displayed similar prognostic power regardless of primary tumor location.
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- **Mural Intracholecystic Neoplasms Arising in Adenomyomatous Nodules of the Gallbladder: An Analysis of 19 Examples of a Clinicopathologically Distinct Entity**
The American journal of surgical pathology 2020 Dec;44(12):1649-1657
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33060404
Intracholecystic neoplasms (ICNs) (pyloric gland adenomas and intracholecystic papillary neoplasms, collectively also called intracholecystic papillary/tubular neoplasms) form multifocal, extensive proliferations on the gallbladder mucosa and have a high propensity for invasion (>50%). In this study, 19 examples of a poorly characterized phenomenon, mural papillary mucinous lesions that arise in adenomyomatous nodules and form localized ICNs, were analyzed. Two of these were identified in 1750 consecutive cholecystectomies reviewed specifically for this purpose, placing its incidence at 0.1%. Median age was 68 years. Unlike other gallbladder lesions, these were slightly more common in men (female/male=0.8), and 55% had documented cholelithiasis. All were characterized by a compact multilocular, demarcated, cystic lesion with papillary proliferations and mucinous epithelial lining. The lesions' architecture, distribution, location, and typical size were suggestive of evolution from an underlying adenomyomatous nodule. All had gastric/endocervical-like mucinous epithelium, but 5 also had a focal intestinal-like epithelium. Cytologic atypia was graded as 1 to 3 and defined as 1A: mucinous, without cytoarchitectural atypia (n=3), 1B: mild (n=7), 2: moderate (n=2), and 3: severe atypia (n=7, 3 of which also had invasive carcinoma, 16%). Background gallbladder mucosal involvement was absent in all but 2 cases, both of which had multifocal papillary mucosal nodules. In conclusion, these cases highlight a distinct clinicopathologic entity, that is, mural ICNs arising in adenomyomatous nodules, which, by essentially sparing the "main" mucosa, not displaying "field-effect/defect" phenomenon, and only rarely (16%) showing carcinomatous transformation, are analogous to pancreatic branch duct intraductal papillary mucinous neoplasms.
- **Pitfalls in Morphologic Diagnosis of Pathogens: Lessons Learned From the Pseudo-Cystoisospora Epidemic**
International journal of surgical pathology 2020 Oct;():1066896920960813
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33016162
Multiple groups have recently reported involvement of the gallbladder mucosa of immunocompetent patients by cystoisospora organisms. However, this has recently been disproved with the support of molecular and ultrastructural studies. Here we present a summary of these events, recounting how this pseudo-Cystoisospora epidemic began and ended. This review also highlights the important role played by ancillary techniques in supplementing the morphologic diagnosis of pathogens.
- **Incidence and significance of GATA3 positivity in gallbladder adenocarcinoma**
Human pathology 2020 Sep;106():39-44
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32991930
GATA3 immunostaining is a sensitive marker for mammary and urothelial carcinomas. It is routinely used in surgical pathology during workup of carcinomas of unknown origin. To the best of our knowledge, this is the first focused study of GATA3 expression in gallbladder adenocarcinomas. In this study, we evaluated GATA3 expression in 38 gallbladder adenocarcinomas. Eight of 38 (21%) gallbladder adenocarcinomas were positive for GATA3. The expression of GATA3 tended to be moderate to strong when present. It was patchy (<50% positivity) in 4 cases, characterized by discrete clusters or groups of malignant cells with areas of intervening negative tumor cells, whereas it was diffuse (>50% positivity) in the other 4 cases. GATA3 expression did not show any significant correlation with clinicopathologic features such as sex, histologic grade, perineural invasion, vascular invasion, pathologic stage, or distance metastasis. The results of our study show that a subset of gallbladder adenocarcinomas (21%) can be GATA3 positive. Awareness of this phenomenon is important while working up GATA3-positive carcinomas immunohistochemically.
- **Claudin-18 as a Marker for Identifying the Stomach and Pancreatobiliary Tract as the Primary Sites of Metastatic Adenocarcinoma**
The American journal of surgical pathology 2020 Dec;44(12):1643-1648
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32925194
Identification of the primary site of cancer is essential for the treatment of patients with cancer. Numerous immunohistochemical markers have been developed to determine the differentiation of tumor cells and suggest possible primary sites, but markers of gastric and pancreatic adenocarcinomas are still lacking. Claudin-18 is a tight-junction protein uniquely expressed in gastric epithelial cells and has been shown to be expressed in gastric and pancreatic adenocarcinoma. Whether claudin-18 can be used as a marker for identifying the primary site of cancer is still unclear. In this study, we used the immunohistochemical method to stain claudin-18 in tissue arrays containing 575 carcinomas from different anatomic sites and representative sections of 157 metastatic adenocarcinomas. In the group of primary tumors, claudin-18 was frequently expressed in gastric, pancreatic, and pulmonary mucinous adenocarcinomas. Half of cholangiocarcinomas and ovarian mucinous carcinomas and some colorectal and pulmonary adenocarcinomas were also positive for claudin-18. In the metastatic cohort, 15 of 17 (88%) gastric adenocarcinomas, 18 of 23 (78%) pancreatic adenocarcinomas, and 4 of 7 (57%) cholangiocarcinomas and gallbladder adenocarcinomas were positive for claudin-18. Only 4 tumors that originated outside the stomach and pancreatobiliary tract were positive for claudin-18. After normalization to the tumor frequency, the sensitivity of claudin-18 for identifying the stomach and pancreatobiliary tract as primary tumor sites was 79%, and the specificity was 93%. The positive and negative predictive values were 76% and 94%, respectively. In conclusion, claudin-18 represents a sensitive and specific marker for stomach and pancreatobiliary adenocarcinoma that may be a useful diagnostic tool in routine surgical pathology.
- **Reduced MFAP5 expression in stroma of gallbladder adenocarcinoma and its potential diagnostic utility**
Virchows Archiv : an international journal of pathology 2020 Sep;():
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32895766
The diagnosis of invasive adenocarcinoma of the gallbladder can sometimes be challenging. The presence of true desmoplastic reaction facilitates the diagnosis of invasion. However, desmoplasia-like changes can be observed in benign gallbladder conditions, and recognition of desmoplasia may be challenging based on morphology. In this study, we tested the expression pattern of microfibril-associated protein 5 (MFAP5), a promising immunohistochemical marker for desmoplasia, in benign gallbladders with desmoplasia-like reaction and gallbladders with invasive adenocarcinoma. We also evaluated the diagnostic utility of MFAP5 in challenging cases with an interobserver agreement study. The results showed that all benign cases retained intact/positive MFAP5 staining pattern in periglandular connective tissue, whereas 79.3% (23 out of 29) of cases of adenocarcinomas demonstrated diffuse and complete loss of MFAP5 staining in the tumor stroma. Interobserver agreement was improved by 2.66 times when images of MFAP5 immunohistochemistry were provided. In conclusion, MFAP5 expression is downregulated in the desmoplastic stroma of gallbladder adenocarcinoma and may provide a useful diagnostic marker in difficult cases.
- **Details of human epidermal growth factor receptor 2 status in 454 cases of biliary tract cancer**
Human pathology 2020 Nov;105():9-19
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32891647
Human epidermal growth factor receptor 2 (HER2)-targeted therapy has improved clinical outcomes in patients with HER2-positive breast and gastric cancers, although ineffective or recurrent cases are present. One reason for this is the heterogeneity of HER2 expression in cancer cells. The aim of this study was to investigate the clinicopathological characteristics and HER2 status of patients with biliary tract cancers (BTCs). We examined HER2 protein expression by immunohistochemistry, HER2 gene amplification by fluorescence in situ hybridization, and both HER2 protein and gene levels simultaneously by gene-protein assay. Samples were collected from 454 patients who underwent surgical resection for BTCs (110 intrahepatic cholangiocarcinomas [ICC], 67 perihilar extrahepatic cholangiocarcinomas [ECC-Bp], 119 distal extrahepatic cholangiocarcinomas [ECC-Bd], 80 gallbladder carcinomas [GBC], and 79 ampullary carcinomas [AVC]). HER2 status was assessed according to the guidelines for HER2 testing in gastroesophageal adenocarcinoma. HER2-positive status was detected in 14.5% of BTCs (3.7% of ICC, 3.0% of ECC-Bp, 18.5% of ECC-Bd, 31.3% of GBC, and 16.4% of AVC). Furthermore, HER2-positivity tended to correlate with low histological grade, tumor histology, and macroscopic features in certain tumors. HER2 heterogeneity was common and highly frequent (83%) in BTC cases. Reduced HER2 protein expression in the deeper invasive areas with simultaneous dedifferentiation was frequently observed in HER2-positive cancer cells. The findings of this study suggest that a large subgroup of HER2-positive BTC cases can be considered for HER2-targeted therapy. Moreover, the HER2 status in BTCs should be determined carefully using a sensitive approach toward larger cancer tissues.
- **Testing for ROS1, ALK, MET, and HER2 rearrangements and amplifications in a large series of biliary tract adenocarcinomas**
Virchows Archiv : an international journal of pathology 2020 Jul;477(1):33-45
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32447492
Biliary tract carcinomas are divided into intrahepatic, perihilar, distal extrahepatic cholangiocarcinomas, and gallbladder adenocarcinomas. Therapies targeting ROS1, ALK, MET, and HER2 alterations are currently evaluated in clinical trials. We assessed ROS1 and ALK translocations/amplifications as well as MET and HER2 amplifications for each tumor subtype by fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC) in 73 intrahepatic, 40 perihilar bile duct, 36 distal extrahepatic cholangiocarcinomas, and 45 gallbladder adenocarcinomas (n = 194). By FISH, we detected targetable alterations in 5.2% of cases (n = 10): HER2 and MET amplifications were found in 4.1% (n = 8) and 1.0% (n = 2), respectively. The HER2-amplified cases were mostly gallbladder adenocarcinomas (n = 5). The MET- and HER2-amplified cases were all positive by IHC. Fourteen cases without MET amplification were positive by IHC, whereas HER2 over-expression was detected by IHC only in HER2-amplified cases. We detected no ALK or ROS1 translocation or amplification. Several alterations were consistent with aneuploidy: 24 cases showed only one copy of ROS1 gene, 4 cases displayed a profile of chromosomal instability, and an over-representation of centromeric alpha-satellite sequences was found in five cases. We confirm a relatively high rate of HER2 amplifications in gallbladder adenocarcinomas and the efficacy of IHC to screen these cases. Our results also suggest the value of IHC to screen MET amplification. Contrary to initial publications, ROS1 rearrangements seem to be very rare in biliary tract adenocarcinomas. We confirm a relatively high frequency of aneuploidy and chromosomal instability and reveal the over-representation of centromeric alpha-satellite sequences in intrahepatic cholangiocarcinomas.
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- **Interobserver agreement in pathologic evaluation of bile duct biopsies**
Human pathology 2020 Oct;107():29-38
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=33129823
Intraductal biopsy is commonly used for preoperative evaluation of the etiology of biliary strictures. Interpretation of intraductal biopsies is frequently challenging. The diagnosis often suffers from interobserver disagreement, which has not been studied in the literature. We sought to assess interobserver concordance in the interpretation of intraductal biopsies. Eighty-five biopsies were retrieved, falling into five diagnostic categories: negative for dysplasia (NED), indefinite for dysplasia (IND), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and carcinoma (CA). Eight gastrointestinal pathologists blindly reviewed all the slides. Agreement among pathologists was analyzed using Fleiss κ and weighted concordance coefficient S∗. A face-to-face consensus/training session was held to discuss the classification criteria, followed by a second round review. The overall interobserver agreement was fair in the first round review (κ = 0.39; S∗ = 0.56) and improved to moderate in the second round review (κ = 0.48; S∗ = 0.69). The agreement before and after consensus meeting was substantial to nearly perfect for CA (κ = 0.65, S∗ = 0.83; and κ = 0.80, S∗ = 0.91), fair for HGD (κ = 0.28, S∗ = 0.69; and κ = 0.40, S∗ = 0.63), and moderate for NED (κ = 0.47, S∗ = 0.50; and κ = 0.47, S∗ = 0.53). Agreement improved from fair to moderate for LGD (κ = 0.36, S∗ = 0.61; and κ = 0.49, S∗ = 0.71) and slight to fair for IND (κ = 0.16, S∗ = 0.51; and κ = 0.33, S∗ = 0.50). Compared with Hollande's fixed specimens, the agreement was higher in almost all diagnostic categories in formalin-fixed biopsies. Overall, interobserver concordance was improved after a consensus/training session. Interobserver reproducibility was high at the end of the diagnostic spectrum (CA) but fair to moderate for other diagnostic categories.
- **Histological evaluation of tumor differentiation score and prognosis of extrahepatic bile duct cancer: A proposal for a new histological grading system**
Pathology international 2020 Nov;70(11):857-864
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32909295
Extrahepatic bile duct (EHBD) cancer is a devastating cancer, and more common in Asian countries than in Western countries. Histological grading continues to be a highly relevant factor in prognosis and management of many kinds of cancer, however no uniform histological grading system exists for EHBD cancer. Histological heterogeneity within tumors is a problem in the evaluation of EHBD cancer. We developed an EHBD histological grading scheme to evaluate tumor differentiation pattern, and statistically analyzed its relationship with prognosis. In the present study, 257 surgically resected EHBD cancers were reviewed and their histological glandular differentiation (HGD) pattern was scored, and then we summed up the most and second most predominant scores. These scores were statistically analyzed for their relationship with patient prognosis. Patients showed a trend of shortening recurrence-free survival (RFS) and overall survival (OS) in association with higher HGD scores. In multivariate analyses, HGD score was determined to be an influential factor in RFS (P = 0.00041) and OS (P < 0.0001). In addition, combining HGD score and lymph node status correctly stratified patient prognosis in RFS. In conclusion, this new HGD scoring system is highly practical and has powerful prognostic value for EHBD cancer.
- **Prognostic effects of histology-based tumour microenvironment scores in resected distal bile duct cancer**
Histopathology 2020 Sep;77(3):402-412
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32473032
AIMS: Histology-based tumour microenvironment (TME) scores are useful in predicting the prognosis of gastrointestinal cancer. However, their prognostic roles in distal bile duct cancer (DBDC) have not been previously studied. This study aimed to evaluate the prognostic significance of the TME scores using the Klintrup-Mäkinen (KM) grade, tumour stroma percentage (TSP) and the Glasgow microenvironment score (GMS) in resected DBDC. METHODS AND RESULTS: Eighty-one patients with DBDC who underwent curative resection were enrolled. DBDC was graded according to KM grade, TSP and GMS. A high KM grade was found in 19 patients (24%) and a high TSP was found in 47 patients (58%). A high TSP was significantly correlated with a low KM grade (P < 0.001). The distribution of the GMS, which was developed by combining the KM grade and TSP, was as follows: 0 (n = 19, 24%), 1 (n = 19, 24%) and 2 (n = 43, 52%). A low KM grade, high TSP and high GMS were significantly associated with short overall survival (OS) (P < 0.001) and relapse-free survival (RFS) (P < 0.001). Furthermore, multivariate analysis showed that a low KM grade [hazard ratio (HR) = 3.826; confidence interval (CI) = 1.650-8.869; P = 0.014], high TSP (HR = 2.193; CI = 1.173-4.100, P = 0.002) and high GMS (HR = 7.148; CI = 2.811-18.173) were independent prognostic factors for short RFS; a low KM grade (HR = 4.324; CI = 1.594-11.733) and high GMS (HR = 6.332; CI = 2.743-14.594) were independent prognostic factors for short OS. CONCLUSION: Histology-based TME scores, including the KM grade, TSP and GMS, are useful for predicting the survival of patients with resected DBDC.
- **Tiny but mighty: use of next generation sequencing on discarded cytocentrifuged bile duct brushing specimens to increase sensitivity of cytological diagnosis**
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 2020 10;33(10):2019-2025
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32457409
Bile duct brushing (BDB) is used to evaluate pancreatobiliary lesions as it widely samples lesions with a low complication rate. Cytological evaluation of BDB is a specific but insensitive test. There is limited literature on the use of post-cytocentrifuged (PCC) samples, which are usually discarded, for next-generation sequencing (NGS) as an adjunct to cytological diagnosis of BDB. In this study we investigate whether molecular analysis by NGS of PCC specimens improves the sensitivity of diagnosis. PCC samples from 100 consecutive BDB specimens spanning 93 unique patients were retained. DNA was extracted and mutational analysis was performed agnostic of morphologic or clinical findings. Each BDB specimen was characterized as negative, atypical or positive based on morphological analysis by trained cytopathologists. Performance characteristics for mutational profiling and morphological analysis were calculated on the basis of clinicopathologic follow-up. There was sufficient clinicopathologic follow-up to classify 94 of 100 cases as either malignant (n = 43) or benign (n = 51). Based on morphologic analysis of cytology, these 94 cases were classified as either benign (n = 55), atypical (n = 18), or as at least suspicious or positive for malignancy (n = 21). Morphologic analysis of cytology showed a sensitivity of 49% and a specificity of 100% if atypical cases were considered negative. NGS revealed oncogenic alterations in 40/43 (93%) of malignant cases based on clinicopathologic follow-up. The most common alterations were in KRAS and TP53, observed in 77% and 49% of malignant cases respectively. No alterations were observed in the 51 benign cases classified based on clinicopathologic follow-up. Supplementing cytomorphologic analysis with molecular profiling of PCC by targeted NGS analysis increased the sensitivity to 93% and maintained specificity at 100%. This study provides evidence for the utility of NGS molecular profiling of PCC specimens to increase the sensitivity of BDB cytology samples, although studies with larger cohorts are needed to verify these findings.
- **Utility of DNA flow cytometry in distinguishing between malignant and benign intrahepatic biliary lesions**
Virchows Archiv : an international journal of pathology 2020 Oct;477(4):527-534
PubMed: https://www.ncbi.nlm.nih.gov/pubmed/?term=32296928
The distinction between well-differentiated intrahepatic cholangiocarcinoma (iCCA) from its morphological mimics such as bile duct adenoma (BDA) and hamartoma (BDH) can be challenging, particularly in small biopsies. Although a few cases of BDA and BDH have been reported to undergo malignant transformation into iCCA, their neoplastic versus benign nature remains debated. DNA flow cytometry was performed on 47 formalin-fixed paraffin-embedded samples of iCCA, 14 BDA, and 18 BDH. Aneuploidy was detected in 22 iCCA (47%) but in none of the 32 BDA and BDH samples. Among the 34 iCCA patients who underwent complete resection and were followed up to tumor recurrence, tumor-related death, or at least for 1 year, the overall recurrence or death rates (regardless of flow cytometric results) were 18, 56, and 71% within 1, 3, and 5 years, respectively. The 1-, 3-, and 5-year recurrence or death rates in 18 iCCA patients with aneuploidy were 28, 66, and 66%, respectively, whereas 16 iCCA patients in the setting of normal DNA content had 1-, 3-, and 5-year rates of 6, 44, and 72%, respectively. Although aneuploid tumors were associated with worse outcomes during the first 3 years, this difference was not statistically significant (hazard ratio = 1.4, p = 0.473) in the present sample size. In conclusion, the frequency of aneuploidy was significantly higher in iCCA (47%) than in its benign morphological mimics (0%), suggesting that it may potentially serve as a diagnostic marker of malignancy in challenging situations. Our findings also suggest that most BDAs and BDHs, if not all, are benign entities and may not represent precursor lesions to iCCAs that often harbor aneuploidy. Although a larger cohort will be necessary to further determine the prognostic significance of aneuploidy in iCCA patients after resection, the patients with aneuploid tumors may have a higher risk for tumor progression, especially during the first 3 years.
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