CARCINOGEN RISK ASSESSMENT - A NECESSARY DILEMMA

Carcinogen risk assessment is the process by which an attempt is made to estimate human risk due to carcinogens, from the results of animal studies. It is based upon a number of prudent default assumptions, tha t is, assumptions that cannot be proved scientifically because either the basic concept is philosophical in nature or because the amount of scientific evidence required is too costly to obtain even on a world-w ide basis. Recently, scientific effort has shown that more and more ex amples have been described suggesting these examples do not behave in the way indicated by the default assumptions. Since carcinogen risk as sessment processes were initiated, it has been demonstrated that cance r may arise by four or more different mechanisms. It is the purpose of this paper to enquire whether consideration of these basically differ ent mechanisms may facilitate carcinogen risk assessment. (C) 1997 Els evier Science Ireland Ltd.