Chemical carcinogenesis: mycotoxins and other chemicals to which humans are exposed.

HCC occurs in a higher incidence in some subsets of human populations residing in specific geographic areas around the world. These include black populations residing south of the Sahara, particularly in South and East Africa; in populations of Southeast Asia and the Western Pacific; in India, China, and in some other circumscribed areas. These epidemiologic observations strongly suggest that environmental factors are involved in the etiology of HCC. Evidence from human and animal data point toward a multicausal etiology, including dietary or environmental contamination with mycotoxin carcinogens, acting in concert with hepatitis B viral infection and, in some areas, with malnutrition. Dietary factors that appear to influence susceptibility to HCC include fat, protein and amino acids, vitamin A, selenium, and zinc. In addition, alcohol consumption, environmental chemicals that are natural or man made, and genetic predisposition must also be considered. It seems likely that identification of etiologic agents (hepatitis B infection, aflatoxin, malnutrition) and correction or prevention of these are the most promising means for controlling HCC in man.