Splenocytes from immunized mice in different groups were restimulated with the recombinant PD-L1 protein ex vivo and then cocultured with 51Cr-labeled syngeneic target PD-L1-expressing pancreatic cancer cells (Panc02-PD-L1) at various E:T ratios to measure the specific killing. This evidence concerns the gene CD274 and familial pancreatic carcinoma.