ABSTRACT
The two-stage models of carcinogenesis as proposed by S. H. Moolgavkar and A. G. Knudson have received considerable attention among cancer epidemiologists and cancer researchers and have been suggested as a major model for assessing risks of environmental agents. This chapter presents a brief survey of the literature and some biological evidence supporting the models. It demonstrates how the two-stage models may be used to assess risks of environmental agents. The chapter is devoted to the derivation of probability distributions of numbers of tumors and the means and variances of the numbers of tumors. The usefulness of mathematical models is to provide a basis to interpret fundamental biological phenomena and to suggest experiments. Moolgavkar has demonstrated that the two-stage models could be used to relate actions of sex hormones with the risk factors of breast and endometrium cancers of women.
