Worldwide, chronic HBV infection accounts for approximately 50% of all cases
of hepatocellular carcinoma and virtually all childhood cases. In endemic areas in
Asia and Africa, where HBV infection is transmitted from mother to newborn, up
to 90% of infected persons have a chronic course, with frequent integration of HBV
into host DNA. Although HBV can cause hepatocellular carcinoma in the absence
of cirrhosis, the majority (70 to 80%) of patients with HBV-related hepatocellular
carcinoma have cirrhosis. The risk of hepatocellular carcinoma among persons with
chronic HBV infection (those who are positive for the hepatitis B surface antigen
[HBsAg]) is further increased if they are male or elderly, have been infected for a
long time, have a family history of hepatocellular carcinoma, have been exposed to
the mycotoxin aflatoxin, have used alcohol or tobacco, are coinfected with HCV or
hepatitis delta virus, have high levels of HBV hepatocellular replication (as indicated