Contributions of polymorphisms in miR146a, miR196a, and miR499 to the development of hepatocellular carcinoma.

Hepatocellular carcinoma is one of the most common malignant tumors worldwide; it is estimated that there were 782,000 new cases in 2012. MicroRNAs (miRNAs) play an important role in carcinogenesis by regulating oncogenes and tumor suppressors. We investigated the role of miR-146a, miR-196a2, and miR-499 polymorphisms in the risk of hepatocellular carcinoma in a Chinese population. Hepatocellular carcinoma patients (175) and healthy controls (302) were recruited between April 2013 and March 2015. Genotype analysis of miR-146a, miR-196a2, and miR-499 polymorphisms was carried out by polymerase chain reaction-restriction fragment length polymorphism. There was a significant difference between the genotype distribution of miR-196a2 in hepatocellular carcinoma patients and controls (X(2) = 17.23, P < 0.001). CG and GG miR-146a genotypes significantly elevated the risk of hepatocellular carcinoma compared with the CC genotype, with adjusted ORs (95%CI) of 3.05 (1.07-8.70) and 4.96 (1.64-14.97), respectively. In the recessive model, the CG + GG genotype had a 3.75-fold risk of hepatocellular carcinoma compared with the CC genotype, with an adjusted OR (95%CI) of 3.75 (1.39-10.11). However, no significant association was observed between miR-196a2 and miR-499 variants and risk of hepatocellular carcinoma in the co-dominant, dominant, and recessive models. The miR-146a polymorphism is a G to C substitution that causes a mismatch in the stem-loop of miRNA, which influences how the expression and transcriptional regulation of miRNA affects its target genes. Our study revealed that the GG and CG genotypes of miR-146a increased the risk of hepatocellular carcinoma in the Chinese population.