Based on the previous study, Wu et al. (2020) found that DNMT1 could suppress the expressions of hMLH1 and hMSH2 via promoting their promoter methylation, thus promoting cell proliferation in epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC). The gene discussed is MSH2; the disease is non-small cell lung carcinoma.