TP53 and neoplasm: To confirm that mutant p53 was expressed and stabilized in the MMTV-Hras/p53R172H/R172H tumors, and to characterize the expression patterns of mutant p53 protein in the tumor tissues, western blotting and immunohistochemical analysis were performed on tumors of each genotype, using an antibody that detects both wild-type and mutant p53.