TP53 and neoplasm: Many tumor-associated mutant p53 (mutp53) proteins not only lose the tumor suppressive function of wild-type p53 (wtp53), but also gain new oncogenic activities independently of wtp53, which is defined as mutp53 gain-of-function (GOF) (Freed-Pastor and Prives, 2012; Muller and Vousden, 2014).