Review Article
Patrick A Riley
Abstract
A two-stage model of carcinogenesis, based on the generation of a defect in the vertical transmission of epigenetic information, is outlined. The essential property of the model exhibits an age-related increase in cancer incidence proportional to the number and proliferation rate of the population of stem cells of different tissues. In the light of this, the paradoxical similarity of cancer incidence rates in animals of differing size (such as man and elephants) is discussed in relation to the possible significance of a proofreading mechanism in diminishing the transmission frequency of epigenetic error.