Update reference signatures from COSMIC v3.1

[ShixiangWang]

I am discussing with COSMIC team about origin of SBS84-SBS90

[ShixiangWang]

Reply from COSMIC team

Dear Shixiang,
The Nature Feb 2020 paper was the base for the v3 signatures (included in
COSMIC in May 2019), also including SBS84-85. The six new signatures in v3.1
were added after manual curation of new relevant literature. Specifically
SBS86-87 were derived from Li et al. 2020 Blood
(https://doi.org/10.1182/blood.2019002220); SBS88 and ID18 from
Pleguezuelos-Manzano et al. Nature 2020
(https://doi.org/10.1038/s41586-020-2080-8), Lee-Six et al. Nature 2019
(https://doi.org/10.1038/s41586-019-1672-7) and Boot et al. BioRxiv 2019
(https://doi.org/10.1101/368753); SBS89 from Lee-Six et al. Nature 2019; and
SBS90 from Boot et al. bioRxiv 2019.

Although we don't specify specific references in the COSMIC Mutational
Signatures web site at the moment, we do plan to in future releases.

Kind regards,
Dave