Hepatocellular carcinoma (an approach to the study of risk factors in human cancer).

Risk factors can be used to formulate hypotheses on the aetiology and pathogenesis of site specific cancers. Persistent infection with hepatitis B virus (HBV), chronic liver disease, and maleness are associated with a greatly increased risk of developing primary hepatocellular carcinoma (PHC). A model for the pathogenesis of this tumour is proposed that does not involve integration of the HBV genome into the tumour cell. If chronic infection with HBV is necessary for the development of chronic liver disease and PHC, prevention of PHC could be accomplished by prevention of infection with HBV. A vaccine against HBV could be accomplished by prevention of infection with HBV. A vaccine against HBV has been developed; if it is effective, we can predict that its use in endemic areas will be accompanied by an eventual fall in the incidence of PHC.