To investigate the cause of the upregulated expression in colorectal cancer, we analyzed the DNA copy number variation and promoter methylation level of ACE2 and TMPRSS2. We found DNA copy number variations were not relevant to expression of ACE2 and TMPRSS2. We then examined the promoter methylation levels of these two genes in colorectal cancer. The gene discussed is TMPRSS2; the disease is colorectal cancer.