Tumor promoting effects benzo pyrene

The tumorigenic effect of benzo[a]pyrene was retarded by the creosote oil, neutral distillate, neutral residue, and phenolic fractions. However, in three instances this effect was apparently related to skin damage associated with the treatments rather to a specific inhibitory effect. Only the phenolic fraction seemed to exhibit a primary antagonistic effect. Three other fractions (basic, neutral, and a low concentration of neutral distillate) exhibited apparent tumor promoting effects. 

Phenol has been regarded as an important tumor promoter in cigarette smoke condensate. .. [but our] work indicates it is inactive in cocarcinogenesis and, indeed, has a slightly inhibitory effect on benzo[a]pyrene carcinogenesis. 

The effect of phenol on benzo[a]pyrene (B[a]P) carcinogenicity has been examined (Van Duuren and Goldschmidt 1976 Van Duuren et al. 1971, 1973). Dermal application of 3 mg phenol in acetone simultaneously with 5 g B[a]P resulted in significantly fewer tumors than application of B[a]P alone. Application surface areas were not reported and could not be estimated from the description of the application procedure. Mice treated dermally with B[a]P followed by dermal application of brewed tea on alternate days over a period of 55 days developed epithelial cell carcinoma or exhibited various stages of squamous cell tumors (Kaiser 1967). The brewed tea contained an unspecified level of phenol, the presumed cancer promoter in this experiment, as well as cresols and dimethylphenols. 

DEHP did not induce forestomach tumors in ICR mice administered approximately 1,171 mg DEHP/kg/ day 2 days/week for 4 weeks and sacrificed after 22 weeks of treatment (Lee et al. 1997). Also in this study, DEHP had no significant effect on the number of forestomach tumors/mouse induced by treatment with benzo[a]pyrene once per week for 4 weeks. Initiation-promotion studies and the role of promotion in the carcinogenicity of DEHP are discussed in Section 3. 5.2 Mechanisms of Toxicity. 

It is also possible that the skin irritant effects of Stoddard solvent could have contributed to the promotion of effects initiated by other components of the mixture. The alkylbenzenes present in Stoddard solvent are not believed to be carcinogenic, based upon negative or weakly positive genotoxicity test results (Andrews and Snyder 1991). However, further animal testing is needed to confirm a lack of carcinogenicity. A dermal study in mice showed that dodecane was a tumor promotor (Sice 1966). Benzo[a]pyrene and benzo[a]anthracene were reported to be 1,000 times more potent in producing tumors when dodecane was used as a diluent than when it was not used (Bingham and Falk 1969). 

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