Finally, moderate inverse correlations were found between TET1 expression and 5-hmdU level (r = − 0.4236, p = 0.035) in persons with polyps, and between TET2 expression and 5-cadC level (r = − 0.5324, p = 0.023) in colorectal cancer patients (Additional file 1: Figures S2–S6). This evidence concerns the gene TET1 and colorectal cancer.