Association between type 2 diabetes mellitus and colorectal adenoma: A retrospective study with insights into Wnt/β-Catenin/TCF7L2 pathway activation

BACKGROUND Previous studies have confirmed the association of type 2 diabetes mellitus with the occurrence of colorectal polyps and adenomas. However, the current research results concerning the extent and specific effect of type 2 diabetes mellitus on the occurrence and development of colorectal adenomas remain inconsistent. AIM To identify and investigate the association between type 2 diabetes mellitus and colorectal adenoma pathogenesis. METHODS This retrospective case-control study reviewed all colonoscopies and definite pathology diagnoses performed in patients admitted to the Department of Gastroenterology, Nanshan People’s Hospital, from January 2015 to December 2017. Colorectal epithelium samples from colorectal adenomas were categorized into two groups: Patients with diabetes mellitus (A + D group; n = 20) and those with no diabetes mellitus (A + ND group; n = 20). The control group (NA + ND) comprised samples from patients without colorectal adenomas or hyperglycemia (n = 10). Carcinoembryonic antigen and insulin-like growth factor-1 levels were analyzed in each group. The expression of transcription factor 7 like 2 (TCF7L2), β-catenin, and Ki67 was detected using immunohistochemistry. RESULTS Type 2 diabetes mellitus was significantly associated with colorectal adenomas (odds ratio = 2.263, 95% confidence interval = 1.252-4.09, P = 0.007). Compared with the A + ND or NA + ND group, carcinoembryonic antigen and insulin-like growth factor-1 levels and TCF7L2, β-catenin, and Ki67 expressions were significantly higher in the A + D group (all P < 0.05). CONCLUSION The results of this small-scale retrospective cohort study indicate a significant association between type 2 diabetes mellitus and colorectal adenomas. The clinical sample experimental evidence in this study indicates that the increased activity and expression of Wnt/β-catenin/TCF7L2 is one of the mechanisms of type 2 diabetes mellitus and colorectal adenomas.