PD-L1 expression in NADCs has not been described other than in two studies of ampulla of Vater carcinoma and SBA19,27; according to the findings of those studies, PD-L1 was expressed in 26.9–44% of duodenal cancers (an incidence that is similar to our present result). This evidence concerns the gene CD274 and carcinoma of the ampulla of vater.