Figure 1.

Tumor-specific changes stabilize mutant p53. (A) p53 IHC of hemangiosarcomas and sarcomas from p53^H/H mice. Dark nuclear staining denotes high mutant p53 levels. (B) Mutant p53 is inherently unstable in normal tissues but stabilized in the absence of Mdm2 or p16^INK4a. p53 IHC of several tissues from wild-type, p53^H/H, p53^H/H Mdm2^−/−, and p53^H/H p16^INK4a−/− mice. Nonspecific staining in the lumen of the intestine is sometimes observed as in the p53^H/H sample.