Stochastic description of initiation and promotion in experimental carcinogenesis.

: Hepatocarcinogens are known to give rise to enzyme altered foci (EAF) in the liver. Since EAF are regarded as intermediate on the pathway to cancer, the promoting effect of chemical compounds on their growth is of critical importance in the assessment of the cancer risk. Using a stochastic description based on the two-mutation model we outline a quantitative analysis of EAF in the rat liver.