Previously, we have studied PD-L1 expression in the same cohort as used in the current study.27 We now used these data to compare PD-L1 expression between both types of cancer and found that 85% of ampullary cancer patients showed PD-L1 expression in their tumours versus 71% of pancreatic cancer patients (p = 0.043). Here, CD274 is linked to familial pancreatic carcinoma.