Moreover, we analyzed the diagnostic ability of SDC2 methylation in different stages of colorectal cancer, and the results showed that methylated SDC2 showed extraordinary ability in diagnosing stage I and II colorectal cancer (sensitivity: 0.80), and there was no significant difference in diagnostic efficacy compared with stage III and IV colorectal cancer (sensitivity: 0.82). The gene discussed is SDC2; the disease is colorectal cancer.