HLA-DOB and cancer: We found that 6 genes (HLA-J, DOA, DOB, DPB1, DQA1, and DQB2) had significantly higher expression levels in the lower-TMB subtype of at least 5 cancer types, while no any HLA gene showed significantly higher expression levels in the higher-TMB subtype of at least 5 cancer types (Additional file 1: Table S6).