Background: We aimed to evaluate the association between the vascular endothelial growth factor (VEGF) gene +936C>T polymorphism and digestive system tumors using a meta-analysis. Methods: Studies of the association between the VEGF+936C>T polymorphism and digestive system tumors published before December 2019 were searched in PubMed, EMBASE, Web of Sciences, the Chinese Biological and Medical Database (CBM), and the China National Knowledge Infrastructure (CNKI). The odds ratio and the corresponding 95% confidence interval were used as the effect indicators. A meta-analysis of original data was performed with different genetic models using the Stata 13.0 software. The reliability of the association was evaluated using the heterogeneity test, sensitivity analysis, false-positive report probability (FPRP), and bias test. Results: This meta-analysis included 37 publications with a total of 8568 digestive system tumor patients and 10,870 cases in the control populations. The overall combined analyses showed that the VEGF+936C>T gene polymorphism was significantly correlated with digestive system cancer susceptibility with the T allele increasing the risk of digestive system cancers. A stratified analysis based on ethnicity showed that the VEGF+936C>T gene polymorphism significantly increased the risk of digestive system tumors in both Asian and Caucasian populations. Additional stratified analyses based on tumor type showed that the VEGF +936C>T gene polymorphism was associated with colorectal cancer, oral cancer, and esophageal cancer. The sensitivity analysis (p < 0.2) and FPRP results also confirmed the reliability of these associations. Conclusions: This meta-analysis supported previous findings that the VEGF +936C>T gene polymorphism is significantly associated with an increased risk of the development of digestive system malignant tumors. This association still requires large-scale epidemiological studies for further validation.
Keywords: +936C>T; VEGF; digestive system cancer; meta-analysis; polymorphism.