Lecturer: Samuel M. Cohen, MD, PhD, DABP, ATS, IATP, of the University of Nebraska Medical Center.
Chemical carcinogenesis involves the production of multiple genetic errors in a single pluripotential (stem) cell in the target tissue, which can be produced either by direct DNA damage (DNA reactive) or by increased cell proliferation. Tumor suppressor genes and proto-oncogenes which safeguard against cancer are the genetic targets of chemical carcinogens. The incidence of chemical carcinogenesis can be enhanced through some inherited diseases, such as retinoblastoma or multiple polyposis coli in which mutations of tumor suppressors or proto-oncogenes occur in all cells. Polycyclic aromatic hydrocarbons are a well-studied class of chemicals that are bioactivated to produce chemical carcinogens. The impact of ethanol, cigarette smoke, and medical conditions such as obesity are also discussed. Model systems are used to predict chemical carcinogenicity and the resulting data may be extrapolated to humans.