Malignant Transformation of Cells Derived from Mouse Prostate by Epoxides and Other Derivatives of Polycyclic Hydrocarbons1

K-region epoxides of benz[a] anthracene, dibenz[a,h] anthracene, and 3-methylcholanthrene have been found to be toxic and more active in producing malignant transformation of cells derived from mouse prostate than their respective parent hydrocarbons and K-region dihydrodiols and phenols. The data support the view that metabolism of these polycyclic hydrocarbons is a prerequisite for their biological activity. 7-Bromomethylbenz [a] anthracene, the K-region epoxide of 7-methylbenz[a] anthracene, and 7-bromomethyl-12-methylbenz [a] anthracene were either inactive or less active in producing malignant transformation than the parent compounds, 7-methylbenz[a] anthracene and 7,12-dimethylbenz [a] anthracene. The 8,9-epoxide (non-K-region) of benz[a] anthracene was much less active than the K-region epoxide of this hydrocarbon; and the K-region epoxides of the noncarcinogenic hydrocarbons, phenanthrene and chrysene did not transform the cells.