PPM1D and neoplasm: In addition to DNA mutations, different mechanisms have been reported to disrupt the tumor suppressive function of p53 in cancer and lead to tumorigenesis, including overexpression of critical p53 negative regulators, such as MDM2, MDM4, and WIP1, and inactivation of p53 by oncoproteins encoded by different tumor viruses, such as simian virus 40 large T antigen, and E6 of human papilloma virus (Vousden and Prives, 2009; Muller and Vousden, 2014; Donehower et al., 2019; Levine, 2019; Zhang et al., 2020).