Primary liver cancer is of multifactorial origin: importance of hepatitis B virus infection and dietary aflatoxin.

Primary liver cancer has a variable incidence worldwide, occurring most frequently in South-East Asia and China, which indicates that environmental factors are important in its aetiology. Although hepatitis B virus and chemical agents are the major risk factors for primary liver cancer, current evidence strongly suggests that it is of multifactorial origin. Aflatoxins are thought to be important because they are common food contaminants and are potent liver carcinogens in a wide variety of animal species. Evidence for the possible interactions between aflatoxin and hepatitis B infection, and their effects on the prevalence of primary liver cancer, is obtained from animal data and epidemiological studies. The risk of developing primary liver cancer following exposure to hepatitis B infection and aflatoxin is shown to be increased and the possible molecular mechanisms involved are discussed.