A Genetic Variant in MiR-146a Modifies Digestive System Cancer Risk: a Meta-analysis

MicroRNAs (miRNAs) negatively regulate gene expression and act as tumor suppressors or oncogenes inoncogenesis. The association between a single nucleotide polymorphism (SNP) in miR-146a rs2910164 andsusceptibility to digestive system cancers was inconsistent in previous studies. In this study, we conducted aliterature search of PubMed to identify all relevant studies published before August 31, 2013. A total of 21independent case-control studies were included in this updated meta-analysis with 9,558 cases and 10,614controls. We found that the miR-146a rs2910164 polymorphism was significantly associated with decreased riskof digestive system cancers in an allele model (OR=0.90, 95%CI 0.87-0.94), homozygote model (OR=0.84, 95%CI0.77-0.91), dominant model (OR=0.90, 95%CI 0.84-0.96), and recessive model (OR=0.85, 95%CI 0.79-0.91), whilein a heterozygous model (OR = 0.99, 95% CI 0.89-1.11) the association showed marginal significance. Subgroupanalysis by cancer site revealed decreased risk in colorectal cancer above allele model (OR=0.90, 95%CI 0.83-0.97) and homozygote model (OR=0.85, 95%CI 0.72-1.00). Similarly, decreased cancer risk was observed whencompared with allele model (OR=0.87, 95%CI 0.81-0.93) and recessive model (OR=0.81, 95%CI 0.72-0.90) ingastric cancer. When stratified by ethnicity, genotyping methods and quality score, decreased cancer risks werealso observed. This current meta-analysis indicated that miR-146a rs2910164 polymorphism may decrease thesusceptibility to digestive system cancers, especially in Asian populations.