The mRNA expression of CCND1 and CYP2S1 genes was high in COAD tumor tissues, while the mRNA expression of GSTM1 gene was low in COAD tumor tissues, and the difference was statistically significant, which was consistent with the previous results of TCGA database and GEPIA2 data analysis. The gene discussed is GSTM1; the disease is colon adenocarcinoma.