HLA-DRB1 and colorectal carcinoma: In particular, both HLA-DRA and HLA-DRB1,3,4,5 were upregulated in CMS1 as compared to other CRC subtypes (Fig 3A), indicating the possibility that MSI-CRC tumors can present antigens with an aid of HLA-DR, a premier antigen-presenting MHC-II molecule.