PDL1, one of the two PD1 ligands, is expressed by both tumor cells and by cells of the tumor microenvironment [56]: its expression by tumor cells promotes neoplastic growth and appears to be of prognostic relevance in pancreatic cancer [38], while its expression on antigen presenting cells in the tumor microenviroment can induce T cell apoptosis [37]. The gene discussed is CD274; the disease is familial pancreatic carcinoma.