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.


Aided in part by Grant CA 7175 from the National Cancer Institute, NIH, and by Grant E 556 from the American Cancer Society.