Reduction of p53 dosage renders mice hypersensitive to 7, 12-dimethylbenz(alpha) anthracene-induced salivary gland tumorigenesis.

BACKGROUND

The role of p53 during the evolutionary steps of experimental salivary gland tumorigenesis has not been fully elucidated.

MATERIALS AND

METHODS

Each genotype group of p53-deficient mice received a single intrasubmandibular gland injection of 1 mg of 7, 12-dimethylbenz(a)anthracene. In addition to the routine histopathological examination, immunohistochemical detection of p53 protein and molecular biological analysis of wild-type p53 allele status in the p53+/- tumors developed were performed.

RESULTS

Fourteen weeks following injection, submandibular gland tumors developed in 100% of p53-/- and 70% of p53+/- mice, whereas only 10% of p53+/+ mice yielded tumors. Salivary gland tumors in p53-deficient mice were predominantly sarcomas (70%). In 64% of p53+/- tumors, overexpression of a mutant version of p53 protein was evident. Loss of the wild-type allele of p53 could not be detected in all p53+/- tumors.

CONCLUSION

The earlier tumor development in p53-deficient mice provides the in vivo evidence that reduction of p53 dosage or possibly p53 haploinsufficiency might be sufficient to promote salivary gland tumorigenesis.