We observed mutual, strong, and positive correlations observed in majority of cancer types between HLA-C, HLA-G, PSMB8, PSMB10, TAPBP, and ERAP1. We also observed strong, positive, and mutual correlations between PSMB5, PSMB6, and PSMB7. In addition, PSMB10 expression was positively correlated with T CD8 levels (in 7 out of 13 datasets) and TAPPB was correlated with TCD4 levels in 6 cancer datasets. This evidence concerns the gene ERAP1 and cancer.