Department of Epidemiology, School of Public Health, China Medical University, Shenyang, 110001, People's Republic of China, firstname.lastname@example.org.
MicroRNAs (miRNAs) are a class of new non-coding RNA, which may play a more important role in the pathogenesis of human cancers. Rs2910164 in miR-146a and rs3746444 in miR-499 are shown to be associated with increased/decreased cancer risk. We performed a meta-analysis to systematically summarize the possible association. We retrieved the relevant articles from PubMed databases. Studies were selected using specific inclusion and exclusion criteria. ORs and 95% CIs were calculated to access the strength of association between microRNA polymorphism and cancer risk. All analyses were performed using the Stata software. Twenty-nine studies were included in this meta-analysis. There were not significant associations between miR-146a rs2910164 and miR-499 rs3746444 polymorphisms with overall cancer risk. In the subgroup analysis by ethnicity, significantly affected cancer risks were found among Asians for both rs2910164 (GC vs. GG: OR = 0.89, 95% CI = 0.82-0.96; CC vs. GG: OR = 0.80, 95% CI = 0.66-0.97; GC + CC vs. GG: OR = 0.86, 95% CI = 0.76-0.97; C vs. G: OR = 0.91, 95% CI = 0.82-1.00) and rs3746444 (GG + AG vs. AA: OR = 1.21, 95% CI = 1.00-1.46). In the tumor type subgroup analysis, rs2910164 C allele decreased the risk of hepatocellular carcinoma (C vs. G: OR = 0.89, 95% CI = 0.80-1.00) and cervical squamous cell carcinoma (C vs. G: OR = 0.72, 95% CI = 0.62-0.84). The rs2910164 in miR-146a and the rs3746444 in miR-499 are likely to be associated with cancer risk.