Low-dose chemical carcinogenesis

The early studies of the kinetics of induction of recessive lethal mutations in Drosophila showed linearity at low doses and no evidence of a threshold. The contention that there is no threshold, or "safe" dose, has dominated genetic thinking on radiation effects and has carried over to chemicals. However, it was long assumed that carcinogenic effects of radiation and chemicals had a threshold. It may be helpful to review some of the recent studies of carcinogenesis. 

Lutz, W. K. (1990). Dose-reponse relationship and low dose extrapolation in chemical carcinogenesis. Carcinogenesis 11(8), 1243-1247. 

Kopp and Portier, 1989) for determining this probability from these types of models. It remains for us to consider how exposure to a chemical carcinogen might alter this time-course. Several mechanisms have been proposed for chemical carcinogenesis which we will consider in the context of this model, emphasizing the Implications of the assumed mechanism on the slope of the dose-response curve at dose zero (i.e. low-dose linear mechanisms vs low-dose non-linear mechanisms). 

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