Hepatitis viruses: Hepatocellular carcinoma

Liver cancer is the fifth most common cancer in men and the seventh in women. The estimated number of new liver cancer cases worldwide has increased by 70 % between 1990 and 2008. It has been projected that the number will increase by 30 % to one million new cases in 2020. Viral hepatitis is the most common cause of hepatocellular carcinoma (HCC) in the world. Hepatitis B virus (HBV) is the most common etiology of HCC in most Asian and African countries and accounts for more than half of all HCCs in the world. Hepatitis C virus (HCV) infection is the leading cause of chronic liver disease and HCC in most Western countries including the USA. The prevalence of HCV infection has increased and the proportion of patients with liver cirrhosis or HCC from HCV has also increased in the USA over the past several decades. Carcinogenesis is a complex and multistep process involving a sequence of tumor initiation, promotion, and progression over several years. Common molecular mechanisms of HCC occurring in the cirrhotic liver include cell-cycle dysregulation, sustained angiogenesis, apoptosis resistance, and cellular immortalization through reactivation of telomerase reverse transcriptase.