Liver Carcinogenesis by Chemicals through Promotion Mechanism Involving Modification of the Cell Membrane

Abstract

Many organochlorine pesticides exert a specific carcinogenic effect on rodent liver, particularly in strains with a high spontaneous background of liver neoplasms. None have been demonstrated to be genotoxic. In contrast, DDT is a liver neoplasm promoter and recently several have been found to inhibit intercellular communication, a property associated with neoplasm promoters. Therefore, it is proposed that these agents produce their liver carcinogenicity through an epigenetic mechanism involving neoplasm promotion. A number of considerations indicate that the hazards of epigenetic carcinogenic agents are distinct from genotoxic carcinogens. Accordingly, the organochlorine pesticides are suggested not to represent a human cancer risk at low levels of exposure.