TP53 and neoplasm: Previous studies from our laboratories have demonstrated that a subset of tumor-derived p53 mutants mediate cell survival in breast cancer cells that expressed them.43 We found that silencing of mutant p53-R273H in MDA-MB-468 cells induced massive apoptosis.43 Importantly, the apoptotic effects following mutant p53 knockdown were independent of TAp63 and TAp73 function.