Evaluation of Coal Tar Tumorigenic Potential in p53 +/- Mice.

The potential of transgenic p53 +/- mice for use as a short-term assay for identifying chemical carcinogens has been primarily evaluated using single chemicals. There have been no reports on the use of this model for assessing the carcinogenic potential of complex organic mixtures containing polycyclic aromatic hydrocarbons (PAHs). In this study, the ability of coal tar to induce a tumorigenic response in transgenic p53 +/- mice was investigated. Transgenic p53 +/- mice were fed diets containing 0.3% manufactured gas plant coal tar (MGP coal tar), 0.3% pharmaceutical grade coal tar (PG coal tar), or 100 ppm benzo[ a ]pyrene (B[ a ]P) for a total of 26 weeks. A group of mice were also treated ip with B[ a ]P (100 mg/kg body weight). Forestomach tumors were observed in 8% of the mice fed PG coal tar. Mice fed 100 ppm B[ a ]P had a 10% incidence of forestomach tumors. Bronchioalveolar adenomas were observed in 23% (3/13) of the mice fed PG coal tar. No lung tumors were observed in any of the mice given a single intraperitoneal injection of B[ a ]P or fed MGP coal tar or B[ a ]P for 260 days. These results are in contrast to results of previous studies performed with A/J and B6C3F1 mice that demonstrated MGP coal tar to be highly tumorigenic in mouse lung. [ABSTRACT FROM AUTHOR]