Wip1 deficiency can lead to the activation of p53, which plays a critical role in tumor suppression and the enhanced ATM/p53-mediated apoptosis (14), thereby resulting in significantly attenuated tumorigenesis in two tumor models including c-myc-induced lymphoma (14, 15) and adenomatosis polyposis coli (Min) intestinal tumorigenesis (3). This evidence concerns the gene PPM1D and neoplasm.