When assessing differing genes between TMB high and low CRC tissue samples, we observed, that the expression level of ERAP1, PDIA3, PSMB6, PSMB9, PSMB10, CALR, CANX, TAP1, TAP2, TAPBP, B2M, and HLA-C was found to be lower in tumors featuring fewer mutations. The gene discussed is ERAP1; the disease is colorectal carcinoma.