In the HER2+ breast cancer sample in which we found a p53 mutation within codon 272 of exon 8, a high percentage of SAβ-gal positive tumor cells was observed (Table 9), indicating that either the p53 mutation has no consequences, or that HER2+ tumor cells still have the ability to senesce even if p53 is mutated. The gene discussed is TP53; the disease is breast cancer.