The oncogenic roles of p53 mutants in mouse models.

Tumors associated with p53 usually contain missense mutations in the p53 tumor suppressor gene rather than deletions of p53, suggesting a growth advantage for cells with missense mutations. The oncogenic roles of p53 mutants have been examined extensively in cell lines. Mouse models that inherit p53 mutations expressed at physiological levels have now been generated to examine the activities of mutant p53 upon tumorigenesis in vivo. Mice with p53 mutations develop tumor spectrums and metastatic phenotypes different from those of mice with a p53-null allele. Embryo fibroblasts with mutant p53 also show increased proliferative and transformation properties. One mechanism for this gain-of-function potential is the inhibition of function of the p53 family members p63 and p73.