Effect of trichloropropene oxide and benzoflavone on polycyclic hydrocarbon carcinogenesis in C3H/He and DBA/2 mice.

Effect of 1,1,1-trichloropropene 2,3-oxide and 7,8-benzoflavone on benzo[a]-pyrene and 3-methylcholanthrene carcinogenesis in the subcutaneous tissues of C3H/He and DBA/2 mice was examined. By a single application of the carcinogen, the incidence of fibrosarcoma was higher and the latency of tumorigenesis was shorter in C3H/He mice than in DBA/2 mice. Treatment with 1,1,1-trichloropropene 2,3-oxide increased the incidence of fibrosarcoma in DBA/2 mice, but decreased the rate in C3H/He mice, when benzo[a]pyrene was used as a carcinogen. On the other hand, in 3-methylcholanthrene carcinogenesis, no effect of the oxide on the tumor incidence was observed. By the simultaneous application of 7,8-benzoflavone with benzo[a]pyrene, the tumor incidence increased, but not so significantly in DBA/2 mice, compared to that treated with benzo[a]pyrene alone, and no appreciable effect was observed in C3H/He mice treated with benzo[a]pyrene, and in both strains of mice with 3-methylcholanthrene. The relationship between the activity of arylhydrocarbon hydroxylase and the change in polycyclic hydrocarbon carcinogenesis is briefly discussed.