OPN1SW and hepatocellular carcinoma: Takahashi et al. [51] first identified HBV mutations through the comparative analysis of full-length HBV isolates (95% genotype C) from 40 HCC patients, and found that mutations in the preS2 region, A1762T, G1764A, and T1753C/A mutations in the BCP region, and G1613A and C1653T mutations in the Enh II region were more frequent in HCC patients.