I'm gonna go yell at my gf.
What did she do?
She gave me cancer.
There's bound to be arguments over the course of any relationship, but in this case it seems you are misguided. Nobody can transmit cancer to you. So, getting mad at her for that reason is just wrong.
No, I'm gonna scream at her for what she did to me.
I understand if you're upset that you have cancer, but your girlfriend did not give it to you. Taking your anger out on her will just make her dislike you and maybe leave you. Try to talk to her in a healthy way.