Association between four common microRNA polymorphisms and the risk of hepatocellular carcinoma and HBV infection

microRNAs (miR/miRNAs) have been demonstrated to function as tumor suppressors and oncogenes, and miRNA polymorphisms may have a role in cancer development. The present study aimed to investigate the association between the miR-146aG>C, miR-149C>T, miR-196a2C>T and miR-499A>G polymorphisms and the risk of hepatocellular carcinoma (HCC) and hepatitis B virus (HBV) infection. A total of 271 patients with HCC and 532 healthy control participants were enrolled in the present study. miR-146aG>C, miR-149C>T, miR-196a2C>T and miR-499A>G polymorphisms were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. A significant difference was identified in the genotype frequency of miR-196a2C>T in the patients in the case group compared with the control group (chi(2)=6.88; P=0.032). Compared with the CC genotype, the miR-196a2 TT genotype was associated with a significantly reduced risk of HCC [odds ratio (OR), 0.62; 95% confidence interval (CI), 0.38-0.991, and a significantly reduced risk was also found in the dominant (OR, 0.69; 95% CI, 0.49-0.98) and recessive (OR, 0.70; 95% CI, 0.46-1.02) models. Moreover, individuals with HBV who were carrying the miR-196a2 CT and TT genotypes had a significantly reduced risk of HCC (OR, 0.62; 95% CI, 0.41-0.95; and OR, 0.39; 95% CI, 0.20-0.73, respectively). In conclusion, the present study found that the miR-196a2C>T polymorphism has a protective effect in patients with HCC, particularly in those with HBV infection.