CYP2D6 and hepatocellular carcinoma: CYP2D6*10 polymorphisms were significantly associated with susceptibility to HCC, as the risk of HCC in individuals carrying the TT genotype decreased by 69.2% [(Odds Ratio (OR) = 0.308, 95% confidence interval (CI) 0.147–0.644, P = 0.002)] when compared with CC genotype carriers (Additional file 2: Table S2), suggesting that the TT genotype is a protective factor for HCC.