Indeed, more than 50% of human cancers harbor mutant p53 [16,17,18], while in most of the remaining cancers, p53 activity is markedly impaired through, for instance, overexpression of the E3-ligase MDM2 (murine double minute 2, also known as HDM2 for its human ortholog) [19,20]. The gene discussed is MDM2; the disease is cancer.