Pri-miR-34b/c rs4938723 TC heterozygote is associated with increased cancer risks: evidence from published data

The promoter region of the microRNA pri-miR-34b/c has a potentially functional polymorphism, rs4938723, located in a typical CpG island. Studies of the association between pri-miR-34b/c rs4938723 polymorphism and risks of various cancers have had inconsistent results. We therefore conducted a meta-analysis of nine studies that included 6,036 cancer patients and 7,490 controls to address this association. Overall, this meta-analysis showed the pri-miR-34b/c rs4938723 TC heterozygote to be significantly associated with increased risk of overall cancers compared with the wild-type TT genotype (P = 0.010, odds ratio (OR) = 1.10, 95 % confidence interval (CI) 1.02–1.18). In stratified analysis, the TC heterozygote was significantly associated with increased cancers risks in digestive tract cancers, in hepatocellular cancer, in Asian population and in the large-sample subgroup. The CC genotypes of rs4938723 were also associated with increased hepatocellular cancer risk but associated with decreased colorectal cancer risk in the stratification analysis by a single cancer type. Thus our meta-analysis suggests that the pri-miR-34b/c rs4938723 TC heterozygote contributes to increased overall cancer risks, as well as shown in digestive tract cancers, in hepatocellular cancer, in Asian population and in the large-sample subgroup. This rs4938723 SNP showed an opposite tendency orientation between the hepatocellular cancer and colorectal cancer risks. Large-sample studies are needed to verify our findings.