HLA-DRB5 and neoplasm: As neoantigen presentation to T cells requires MHC-I or -II proteins that may themselves have variable levels of expression, we utilized MS to additionally quantify the expression of total MHC-I (HLA-A, -B, and -C) and MHC-II proteins (HLA-DRB1, -DRB3, -DRB4, -DRB5, -DPA1, -DPB1, -DQA1, and -DQB1) in each tumor.