MicroRNA variants and colorectal cancer risk: a meta-analysis

Colorectal cancer (CRC) is a multi-factorial disease, and genetic background may contribute to its etiology. Single nucleotide polymorphisms (SNPs) in microRNAs (miRNAs) may be used as specific markers of predisposition for CRC diagnosis and prevention. In this review, we summarize and discuss recent publications evaluating the roles of miRNA SNPs in CRC. A meta-analysis was also carried out to assess the association between the five most frequently studied miRNA SNPs and CRC risk. No relationship was established between this disease and the three SNPs rs11614913, rs2910164, and rs3746444 in miR-196a-2, miR-146a, and miR-499, respectively. However, polymorphisms of miR-149 (rs2292832; CT vs TT: odds ratio [OR] = 0.816, 95% confidence interval [CI] = 0.691-0.963; CC+CT vs TT: OR = 0.834, 95%CI = 0.715-0.972) and pre-miR-27a (rs895819; GG vs AA: OR = 1.534, 95%CI = 1.148-2.049; GG+AG vs AA: OR = 1.324, 95%CI = 1.066-1.645) were found to be associated with CRC in our analysis. In conclusion, the SNPs rs2292832 in miR-149 and rs895819 in pre-miR-27a were associated with CRC susceptibility, whereas rs11614913, rs2910164, and rs3746444 in miR-196a-2, miR-146a, and miR-499, respectively, were not. Further studies should be carried out to validate these findings.