MMR genes are able to maintain genomic stability and thus have an impact on cancer development and progression; therefore, we investigated the correlation of five MMR genes with EPOR. The results showed that EPOR expression was significantly correlated with MLH1, MSH2, MSH6, PMS2, and EPCAM in BRCA, CESC, HNSC, LIHC, ovarian serous cystadenocarcinoma (OV), and thymoma (THYM), and with four of the MMR genes in KIRP, PCPG, STAD, TGCT, and UVM (Figure 10B), and the parts with stronger correlation in pan-cancer are shown in Supplementary Figure 6 (r ≥ 0.3, p < 0.001). The gene discussed is MSH2; the disease is ovarian serous cystadenocarcinoma.