INDUCTION OF LUNG AND LIVER-TUMORS BY FLUORANTHENE IN A PREWEANLING CD-1 MOUSE BIOASSAY

Fluoranthene (FA), a major environmental pollutant, induced lung and liver tumors 6-9 months after intraperitoneal injection of 0.7, 1.75 and 3.5 mg FA into preweanling CD-1 mice. There was a dose-dependent increase in lung tumors with a maximum tumor incidence of nearly 45% and a maximum tumor multiplicity of 0.6-0.7 lung tumors/mouse. No significant difference was noted in lung tumors in the 6 and 9 month bioassays, although fewer tumors were consistently noted in mice treated with the two lowest doses of FA. Indices of lung tumor incidence (ED50) and multiplicity (TM1.0) were similar for the two bioassays and ranged from 18.9-19.5 and 26.2-27.2 Amol respectively. Male mice had up to two times more lung tumors than females but these results were not statistically significant. Liver tumors (nodular hyperplasia) appeared only in FA-treated males but no dose-response relationship was evident. However, liver tumors were observed in only 0-10% of the male mice in the 6 month treatment groups, but in 20-60% of the males in the 9 month groups. Because the CD-1 preweanling mouse responded to the weak lung tumorigen FA, it is a viable, limited-term bioassay for measuring tumorigenicity of PAH and combustion emissions.