MECHANISMS OF NONGENOTOXIC CARCINOGENESIS

Until recently, the mechanism of carcinogenesis has been regarded as a two-stage phenomenon involving damage to the genetic material, which initiates the process, followed by a cell-division stimulus, which pro motes the development of the tumour. However, exposure to some chemica ls has been shown to result in carcinogenesis without involvement of t he initiation step. The mechanism of non-genotoxic carcinogenesis is n ot fully understood, but is believed to involve stimulation of cell di vision with a consequent increased probability of a mutation occurring spontaneously. In this article, Ian Shaw and Huw Jones review the the ories of non-genotoxic carcinogenesis with reference to specific examp les of known non-genotoxic carcinogens.