CANCER RISK ASSESSMENT AT THE CROSSROADS - THE NEED TO TURN TO A BIOLOGICAL APPROACH

Mathematically based carcinogen risk assessment is based on a number o f prudent default assumptions which are becoming progressively less te nable as new scientific evidence is adduced. For example, the assumpti ons that all rodent carcinogens will. be carcinogenic in humans and th at there is no safe dose of any carcinogen may, in specific examples, be shown to be untrue. The mechanisms by which carcinogens exert their effects, especially the induction of DNA lesions, DNA repair of these lesions, and cell proliferation, are considered; it is suggested that with recently developed experimental techniques they might be employe d to develop a more biologically based approach to risk assessment and might avoid at least, some of the pitfalls associated with the presen t mathematically based carcinogen risk assessment models. They might l ead to an improved appreciation of the shape of the carcinogen dose-re sponse curve, at least at medium to high exposure levels. (C) 1996 Aca demic Press, Inc.