Carcinogens and Carcinogenesis in the Colon

Abstract

Studies using labeled precursors of DNA and RNA indicate that colonic neoplasia begins on the surface of the bowel, when normally senescent cells of the epithelium resume mitosis in response to some exogenous stimulus (e.g., something ingested or its metabolic products). The morphology of the tumor is probably determined by the number of cells originally involved. Evidence for this concept of colonic carcinogenesis is detailed.