Authors
Marston CP, Pereira C, Ferguson J, Fischer K, Hedstrom O, Dashwood W-M, Baird WM.

Effect of a complex environmental mixture from coal tar containing polycyclic aromatic hydrocarbons (PAH) on the tumor initiation, PAH-DNA binding and metabolic activation of carcinogenic PAH in mouse epidermis

This study demonstrates that a National Institute of Standards Reference Material 1597 (SRM), a complex mixture of polycyclic hydrocarbons (PAH) extracted from coal tar when applied topically to mouse skin at a concentration of 1 mg produced tumors and increased mortality incidence at 25 weeks. The application of an initiator such as benzo (a) pyrene (BaP) prior to SRM enhanced the number of tumors and mortality rate compared to SRM alone. The ability to produce tumors was correlated with PAH-DNA adducts formation in mouse skin. The quantity of PAH-DNA adducts was greater in the SRM and BaP group compared to BaP alone. Thus although PAH-DNA adducts content reflects a measure of carcinogenic potential, data show it is not the amount of DNA-adduct present but the persistence of the adducts in tissue which is crucial for the induction of chemical-induced dermal carcinogenesis.