Association of hepatitis C virus and hepatocellular carcinoma in the United States.

Hepatocellular carcinoma (HCC) is a common cause of death from cancer on a worldwide basis. Chronic hepatitis B virus (HBV) infection is a well-documented pathogenic factor in the etiology of HCC, accounting for the majority of cases in certain geographic areas where HBV chronic-infection rates are high. Recent studies have implicated hepatitis C virus (HCV) infection as another major etiologic agent of hepatitis B surface antigen (HBsAg)-negative HCC. Studies in Europe have demonstrated that HCV infection is commonly associated with HCC; the prevalence rates of HCV ranged from 39% to 77% of HCC patients in these studies. In areas where HBV infection is endemic, such as Africa and Japan, the prevalence rates of anti-HCV in individuals with HCC have been reported at 29% and 68%, respectively. The significance of HCV and HBV infections in contributing to the occurrence of HBsAg-negative HCC has not been well established in the United States. The clinical consequences of infection with different genotypes of HCV (defined by nucleotide sequence divergence) are largely unknown: several studies have suggested differences among genotypes in terms of clinical expression, disease progression, and response to treatment with interferon. Our recent studies demonstrated that HCV and occult HBV infections account for the majority of cryptogenic HCC cases in the United States. Preliminary studies on the prevalence of HCV genotypes in patients with or without HCC but otherwise matched for hepatic histology did not reveal any association of specific genotype(s) with development of HCC.