PDCD1 and pancreatic ductal adenocarcinoma: Stifter et al. investigated the effect of transporter-mediated tumor antigen expression associated with antigen processing on PD-1/ PD-L1-CD8 T cell priming using pancreatic ductal adenocarcinoma cells (PDACCs) in mice deficient for PD-1/PD-L1-competence [40].