Abstract: Objective To analyze the relationship between DNA methyltransferase 1 (DNMT1) and forkhead box O3a (FOXO3a) in colon cancer and the diagnostic efficacy of combined detection in predicting the occurrence of colon cancer by detecting the levels of DNMT1 and FOXO3a in serum of colon cancer patients. Methods A total of 105 patients with colon cancer diagnosed and treated in Xi'an International Medical Center Hospital from September 2019 to September 2020 were selected as the colon cancer group, and 65 patients with colon polyps diagnosed by biopsy during the same period were selected as control group. The levels of DNMT1 and FOXO3a in serum of patients were detected by real-time fluorescence quantitative PCR. Pearson correlation coefficient method was used to analyze the correlation between the levels of DNMT1 and FOXO3a in serum of patients with colon cancer. Subject operating characteristic curve was used to evaluate the diagnostic values of DNMT1 and FOXO3a levels in colon cancer. Results The serum levels of DNMT1 in the control group and colon cancer group were 0.93±0.28 and 1.34±0.35, compared with the control group, the level of DNMT1 in the colon cancer group was significantly higher, with a statistically significant difference (t=7.990, P<0.001). The serum levels of FOXO3a were 1.04±0.39 and 0.69±0.18, compared with the control group, the level of FOXO3a in the colon cancer group was significantly lower, with a statistically significant difference (t=7.940, P=0.001). The serum levels of DNMT1 and FOXO3a in patients with colon cancer were negatively correlated (r=-0.687, P<0.001). The area under the curve (AUC) of DNMT1 predicting colon cancer was 0.843, the sensitivity was 71.40%, and the specificity was 90.80%. The AUC of FOXO3a predicting colon cancer was 0.812, the sensitivity was 88.60%, and the specificity was 67.70%. The AUC of the two combined predicting colon cancer was 0.859, the sensitivity was 89.50%, and the specificity was 92.30%. Compared with FOXO3a single detection, the predictive value of combined detection of DNMT1 and FOXO3a were higher (Z=1.982, P=0.047). Conclusion The level of DNMT1 in the serum of patients with colon cancer is increased, while the level of FOXO3a is decreased. There is a negative correlation between them in the serum of patients with colon cancer. The combined detection of the DNMT1 and FOXO3a can effectively improve the diagnostic value of colon cancer.

Key words: Colon neoplasms, DNA methyltransferase 1, Forkhead box O3a