Background: Published data regarding associations between the microRNA-146a polymorphism and the risk of gastric cancer are inconclusive. This study aims at evaluating the genetic risk of microRNA-146a polymorphism in gastric cancer.
Methods: A systematic literature search was carried out in Pubmed, Medline (Ovid), Embase, CBM, CNKI, Weipu, and Wanfang databases, covering all available publications (last search was performed on Apr 15th, 2019). Statistical analysis was performed using Revman 5.2 and STATA 10.1 software.
Results: A total of 5,017 cases and 4,869 controls in 14 case-control studies were included in this meta-analysis. No significant association between microRNA-146a polymorphism and gastric cancer risk was observed in all kinds of genetic models (homozygote genetic model CC vs. GG: OR = 0.96, 95% CI = 0.81 - 1.15, p = 0.66; the heterozygote genetic model CG vs. GG: OR = 0.94, 95% CI = 0.86 - 1.02, p = 0.15; the recessive genetic model CC vs. CG + GG: OR = 0.98, 95% CI = 0.91 - 1.05; the dominant genetic model CC + CG vs. GG: OR = 0.94, 95% CI = 0.86 - 1.01, p = 0.1, p = 0.55; and the allele genetic model C vs. G: OR = 0.98, 95% CI = 0.89 - 1.06, p = 0.58). In subgroup analysis, the C allele may be a protective factor for gastric cancer development in the analysis of the dominant genetic model (CC + CG vs. GG) in HCC studies (OR = 0.90, 95% CI = 0.83 - 0.98, p = 0.02) but a risk factor in Japanese when calculated with the recessive genetic model (CC vs. CG + GG) (OR = 1.19, 95% CI = 1.02 - 1.40, p = 0.03).
Conclusions: Based on our meta-analysis, the microRNA-146a polymorphism is unlikely to be a risk factor for gastric cancer in overall population.