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.