ABSTRACT
Carcinogens have been recognized since Percival Pott, and regulatory initiatives have flourished, as anxieties gradually shifted from vanishing acute infections to chronic diseases made more prevalent by longevity gains, and in the wake of concern over ubiquitous industrialization. In the late 1950s, in the heat of public concern over food additives and new pharmaceuticals, US legislators sought the advice of science in the definition of carcinogen standards. Essentially nothing is known of the ultimate molecular events that determine the transformation of normal cells into cancer cells. Using animals to test carcinogens has its roots in basic research where the principal concern was not and is not assessment of real-life risk but the study of the phenomenon of carcinogenesis. Discouraging as it may seem, it is not plausible that animal carcinogenesis experiments can be improved to the point where quantitative generalizations about human risk can be drawn from them.
