Mouse skin tumorigenesis has been used to evaluate the tumorigenic effects of complex mixtures including human respiratory carcinogens. The study examines the quantitative relationships between tumor induction in SENCAR mouse skin and the induction of respiratory cancer in man using four well-established human respiratory carcinogens: emissions from coke ovens, roofing tar pots, diesel engines, and cigarettes. The tumor multiplicity data from mouse skin studies using extracts of particulates from each of the four emission sources is compared. Using the unit risk (the lifetime probability of respiratory cancer death due to a constant lifetime exposure of 1 microg/m3 emissions in the inhaled air) to compare the potency of the four emissions to human respiratory cancer, the relative potency is: coke oven:roofing tar:diesel:cigarette smoke: 1.0:0.39:0.075:0.0024. When fitted to a linear regression the mouse skin tumor data and human lung cancer risks were highly associated. The close association between the two relative potencies suggest that this comparative potency approach can be used in prospective analyses of human respiratory cancer risk to complex emissions, and several examples are proposed. In addition, the similarity of the chemical and toxicological characteristics of complex mixtures is discussed with regard to the prospective use of the comparative potency approach.

"Presented at the Complex Mixtures Meeting, Espoo, Finland." Microfiche.