Single Nucleotide Polymorphisms in miR-122 Are Associated with the Risk of Hepatocellular Carcinoma in a Southern Chinese Population

Single nucleotide polymorphisms (SNPs) in microRNA may affect its expression and regulation of target genes, which may consequently alter individual susceptibility to cancer. In this study we aimed to investigate associations between miR-122 polymorphisms and hepatocellular carcinoma (HCC) in a southern Chinese population. Three selected SNPs in miR-122 (rs9966765, rs1135519, and rs17669) were genotyped in 1050 HCC patients and 1079 cancer-free controls using Sequenom MassARRAY platform and the associations of the three SNPs and HCC risk were evaluated. We found that individuals with the rs1135519 CC genotypes had a significant increased risk of HCC than those with TT genotypes (adjusted OR=2.71, 95% CI=1.15-6.36, and P=0.022), while the rs9966765 CC genotypes showed a borderline significant association with increased risk of HCC when compared with the GG genotypes (adjusted OR=2.38, 95% CI=0.99-5.75, and P=0.052). There was also a significant increased risk of HCC when combining risk genotypes of these loci, i.e., rs1135519 CC and rs9966765 CC. Compared with the low-risk group (0 risk genotype), the high risk group (1-2 risk genotypes) had significantly increased risk of HCC (OR=1.61, 95% CI=1.05-2.44, and P=0.028). Further genotype-expression analysis revealed that cases carrying the CC genotype of rs1135519 had lower levels of miR-122 expression than those with the TT genotype. Our results suggest that SNP of rs1135519 modulates miR-122 expression and contributes to the genetic susceptibility of HCC, either independently or together with rs9966765 in miR-122. Further well-designed studies with lager sample sizes are needed to confirm our findings.