MDM2 and neoplasm: Interestingly, the increase in MDM2 expression by SNP309G not only results in decreased p53 stability and activity in response to DNA damage (Bond et al., 2004; Arva et al., 2005), but also significantly accelerates tumor formation in Li–Fraumeni individuals containing a germline mutation in TP53 (Bougeard et al., 2006).