Given the importance of PPM1D as a key regulator of cellular responses to DNA damage, as well as the frequent detection of gene mutations, gains or amplifications of PPM1D in various cancers resulting in the overexpression of WIP1 or the expression of truncated, oncogenic versions of WIP1 proteins [33,37,59,60], PPM1D stands out as a strong candidate for tumorigenic involvement. This evidence concerns the gene PPM1D and cancer.