TP53 and cancer: Chromosomal amplifications of the 12q13–15 region, which include the MDM2, CDK4 and HMGA2 genes, among others, are a characteristic feature of LPSs.4, 5, 6MDM2 amplification occurs in several cancers and is thus of importance in tumorigenesis.7 MDM2, which is a negative regulator of p53, blocks p53-dependent transcription and recruitment of transcription coactivators, by binding within its N-terminal hydrophobic pocket.