However, various alternative pathways for antigen presentation of endogenous antigens on MHC class II have been proposed.58–60 Our data showing low expression of CLIP on the surface of PDAC cells, despite low HLA-DM, coupled to the cytotoxic activity of CD4+ T-cells toward MHC-II-positive PDAC cells, strengthen the argument that the MHC class II molecules are loaded with tumor-derived antigens, therefore potentially targetable. Here, CD4 is linked to neoplasm.