Potential effects of IL-17A rs2275913 and IL-17F rs763780 polymorphisms on susceptibility to gastric cancer in Chinese population: a meta-analysis.

OBJECTIVE: This meta-analysis aims to clarify the effect of IL-17 polymorphisms on the susceptibility to GCa in the Chinese population. MATERIALS AND METHODS: Relevant pieces of literature were searched in PubMed, Web of School, VIP, and CNKI using the key words as "IL-17, gastric/stomach cancer" or "IL-17 polymorphisms, gastric/stomach cancer susceptibility". The odds ratio (OR) and 95% confidence interval (CI) in the selected studies were calculated using RevMan5.3 and STATA12.0. RESULTS: A total of 12 investigations reporting mutations in IL-17A rs2275913 and IL-17F rs763780 were enrolled. There were 11 studies reporting rs2275913 G>A, involving 3299 cases of GCa patients and 3339 cases of healthy controls. The random-effects model was performed since the heterogeneity test results of the recessive genetic model (GG&GA vs. AA) and the allelic model (G vs. A) of IL-17A rs2275913 G>A were I2>66%/p=0.001. Meanwhile, the dominant genetic model (GG vs. GA&AA) and the super-dominant genetic model (GA vs. GG&AA) of IL-17A rs2275913 G>A were I2< 50%/p>0.05, and the fixed-effects model was used. The meta-analysis showed that IL-17A rs2275913 G>A was positively correlated with GCa susceptibility under four genetic models (p<0.05). Five studies reporting IL-17F rs763780 T>C were enrolled, including 2535 cases of GCa patients and 2402 cases of healthy controls. The heterogeneity test showed that, except for the super-dominant genetic model, the p-value was <0.00001 in the dominant, recessive, and allelic models, and their I2 values were 87%, 88%, and 93%, respectively. Hence, a random-effects model was selected. IL-17F rs763780 T>C was positively correlated with GCa susceptibility under the super-dominant genetic model (p=0.003), rather than the other three models (p>0.05). CONCLUSIONS: IL-17A rs2275913 G>A polymorphism contributes to susceptibility to GCa in the dominant, recessive, allelic, and super-dominant models. Meanwhile, IL-17F rs763780 T>C polymorphism is positively correlated with GCa susceptibility in the super-dominant model.