[Association of miR-146a rs2910164 G/C polymorphism with its abnormal expression and risk of gastric cancer].

OBJECTIVE: To assess the influence of rs2910164 G/C single nucleotide polymorphism (SNP) of the miR-146a gene on its expression and susceptibility to gastric cancer. METHODS: Fifty three gastric cancer patients and six gastric cancer cell lines were selected for determining the miR-146a expression by Taqman quantitative PCR. A model was constructed to assess the influence of miR-146a overexpression on the growth of AGS gastric cancer cells. A case-control study involving 417 gastric cancer patients and 420 cancer-free individuals was then conducted, and the allelic and genotypic frequencies of the rs2910164 G/C SNP were compared. The genotypes of all subjects were determined by using a Taqman allelic discrimination assay. A Taqman assay was also used to quantify mature and pri-miR-146a transcripts among 65 gastric cancer patients with known genotypes. RESULTS: The expression of miR-146a was down-regulated among the 53 gastric cancer patients and six gastric cancer cell lines. Over-expression of miR-146a has suppressed the growth of gastric cancer by inhibiting the G1/S-phase transition of AGS cells. The case-control study showed that subjects with GC/CC genotypes had significantly lower risk for gastric cancer compared with those with GG genotype. In addition, miR-146a G/C SNP has significantly increased the level of mature miR-146a in those with GC/CC genotype compared with GG genotype. CONCLUSION: Down-regulation of miR-146a may play an important role in the pathogenesis of gastric cancer. The rs2910164 polymorphism of the miR-146a gene may reduce the risk of gastric cancer by influencing the processing of mature miR-146a.