Common polymorphisms of the microRNA genes (miR-146a and miR-196a-2) and gastric cancer risk: an updated meta-analysis.

The associations between two common polymorphisms in microRNA genes (miR-146a, dbSNP: rs2910164; miR-196a-2, dbSNP: rs11614913) and gastric cancer risk have frequently been examined; however, the results have often been controversial. This meta-analysis was performed to clarify the association between the two polymorphisms and gastric cancer risk. The literature search primarily utilized PubMed, Embase, SinoMed, and Wanfang databases to identify eligible studies. Odds ratios (ORs) with their 95% confidence intervals (CIs) were analyzed to investigate possible correlations. Subgroup analyses of ethnicity as well as source of controls were also performed. The correlation analysis was based on 11 studies, containing 4690 patients and 6066 controls for miR-146a (C>G) together with 1911 patients and 2484 controls for miR-196a-2 (T>C). For the miR-146a polymorphism, the values of the ORs and 95%CIs were >1, suggesting that a correlation exists. In subgroup analysis of source of controls, a correlation was also identified in the Asian subgroup. However, in Caucasians the ORs and 95%CIs were not distributed on the same side of the critical value 1, contra-indicative of a correlation in this group. For the miR-196a-2 polymorphism, the ORs with 95%CIs of both overall and subgroup analyses were also not restricted to >1 or ˂1. In summary, the results suggested that the miR-146a rs2910164 polymorphism was related to gastric cancer risk in Asians but not in Caucasians, and no distinct correlation seemed to exist between the miR-196a-2 rs11614913 polymorphism and the risk of gastric cancer.