Murine double minute 2 (MDM2), a proto-oncogene, has been found to be upregulated in a variety of cancers and interacts with p53 (Oliner et al., 1992; Bueso-Ramos et al., 1993), thereby promoting degradation of p53 and inhibiting p53-mediated transactivation (Momand et al., 1992; Haupt et al., 1997). Here, TP53 is linked to cancer.