Association between hsa-miR-34b/c rs4938723 T 〉 C promoter polymorphism and cancer risk： a meta-analysis based on 6,036 cases and 6,204 controls

Objective： Emerging evidence shows that microRNAs （miRNAs） function as tumor suppressors or oncogenes in human carcinogenesis. A single nucleotide polymorphism （SNP） located in the pri-miRNA promoter may affect the processing and expression of mature miRNA. However, previous studies showed conflicting results regarding the association of hsa-miR-34b/c rs4938723 T 〉 C promoter polymorphism with cancer. Therefore, we conducted a meta-analysis to determine the association of polymorphism with cancer risk. Methods： A computerized search of PubMed, Web of Science, and Chinese National Knowledge Infrastructure （CNKI） for publications on hsa-miR-34b/c rs4938723 T 〉 C promoter polymorphism and cancer risk was performed and the genotype data were analyzed in a meta-analysis. Odds ratios （ORs） with 95% confidence intervals （CIs） were estimated to assess the association. Test of heterogeneity, cumulative meta-analysis, sensitivity analysis and assessment of bias were performed in our meta-analysis by STATA software 12.0. Results： There was no significant association between hsa-miR-34b/c rs4938723 polymorphism and overall cancer risk in the comparison models. Moreover, subgroup analysis revealed that the variant CT （OR = 1.19, 95% CI： 1.03-1.37） and CC/CT （OR =1.18, 95% CI： 1.03-2.35） genotypes were associated with an increased risk of hepatocellular carcinoma （HCC） compared with wild-type TT genotype. However, a decreased risk of colorectal cancer （CRC） was found in the genetic model of CCFFF （OR =0.66, 95% CI： 0.47-0.92） and CC/CT-TT （OR =0.67, 95% CI： 0.49-0.93）. Conclusions： The results suggest that hsa-miR-34b/c rs4938723 polymorphism may play an opposite role in different types of cancer based on current studies, which is the main origin of heterogeneity in this metaanalysis. Further large-scale studies and functional studies between this polymorphism and cancer risk are warranted.