Hepatitis B Virus-Associated Hepatocellular Carcinoma.

Liver cancer is the fifth most common cancer worldwide in men and the ninth in women. It is also the second most common cause of cancer mortality. Hepatocellular carcinoma (HCC) is the most common type of liver cancer. About 350 million people globally are chronically infected with HBV. Chronic hepatitis B virus (HBV) infection accounts for at least 50% cases of HCC worldwide. Other non-HBV factors may increase HCC risk among persons with chronic HBV infection. Both indirect and direct mechanisms are involved in HCC oncogenesis by HBV. HCC-promoting HBV factors include long-lasting infection, high levels of HBV replication, HBV genotype, HBV integration, specific HBV mutants, and HBV-encoded oncoproteins (e.g., HBx and truncated preS2/S proteins). Recurrent liver inflammation caused by host immune responses during chronic HBV infection can lead to liver fibrosis and cirrhosis and accelerate hepatocyte turnover rate and promote accumulation of mutations. Major breakthroughs have been achieved in the prevention of HBV-associated HCC with HBV vaccines and antiviral therapies.