Initiation and Promotion Activity of Certain Polynuclear Hydrocarbons23

Abstract
When tested as initiators of carcinogenesis per 3.5 cm.2 of mouse skin, 1 µg. of 7,12-dimethylbenz[a]anthracene was very potent, 0.1 µg. of this hydrocarbon had marginal activity, 0.9 µg. of benz[a]anthracene was a little more active than 0.1 µg. of 7,12-dimethylbenz[a]anthracene, and 9-methylanthracene was inactive. Both benz[a]anthracene and 9-methylanthracene were inactive as promoters of carcinogenesis.