TP53 and neoplasm: Bougeard et al. (2006) showed that, among 61 French carriers of a germline p53 mutation (41 affected with cancer), the mean age of tumor onset in those with MDM2 SNP309 GG/GT (19.6 years) was significantly younger than in those with MDM2 TT (29.9 years) (P<0.05) [11].