Models for analyzing data in initiation-promotion studies.

The objective of this paper is to construct a class of models for analyzing data in initiation-promotion (IP) studies. After the application of an initiator in animals IP studies, histochemical and/or histopathologic criteria are used to define the foci that are postulated to be the origin of tumors. Thus, the dynamics of foci growth are of inherent interest in the study of the mechanism of carcinogenesis. In this paper, models to explain these dynamics are developed and can be used to differentiate among proposed mechanisms of tumor formation and promotion. Examples are given to illustrate useful concepts for analyzing data from IP studies.