Environmental liver tumors.

The recent realization that the majority of human carcinomas are induced by chemical agents has raised concern all over the world as to the possible induction of these tumors by environmental factors, in part derived from industrial sources. Both industrial production of chemicals as well as their pollution of the environment have markedly increased and present a hazard not only for workers in contact with carcinogenic agents, but for the population at large exposed to ambient air and food. Storage of compounds such as organochloride pesticides and polychlorinated biphenyls in fat tissue of man has been demonstrated, which enhances the possibility of hidden sources of human carcinogenesis. Indeed, since the initial demonstration of scrotum carcinoma in chimney sweeps by Pott in 1775, many examples of environmental malignancies have been demonstrated in man, such as mesotheliomas and lung carcinomas from exposure to asbestos, lung carcinomas from smoking, leukemias and lymphomas from radiation. Epidemiologic and geographic pathologic studies, many also conducted in Japan, have raised the serious possibility that carcinomas of the gastrointestinal tract, particularly of the stomach and colon and also of the pancreas, are of environmental etiology (Higginson, 1976). The importance of these considerations cannot be overemphasized since the elimination of these hazards would prevent this scourge of humanity.