Mouse skin tumor-initiating activity of benz[j]aceanthrylene in SENCAR mice.

Benz[j]aceanthrylene (B[j]A), a cyclopenta-fused derivative of benz[a]anthracene, has been reported to be an active bacterial cell and mammalian cell gene mutagen, a morphological transforming agent in C3H10T1/2CL8 mouse embryo fibroblasts and a mouse lung tumorigen in strain A/J mice. B[j]A was evaluated as a skin tumor initiator in female SENCAR mice and was found to induce papilloma formation in the range of 40-400 micrograms/mouse. B[j]A was found to be extremely active, inducing 8.7 papillomas/mouse after an initiating dose of 40 micrograms/mouse. At this dose, 100% of the mice bore tumors. Comparison with four other cyclopenta-fused polycyclic aromatic hydrocarbons suggests that B[j]A is extremely potent.