MDM2 and cancer: In the last decade, it has been demonstrated that the single-nucleotide polymorphism (SNP), arginine or proline at codon 72 of the p53 gene, is associated with the risk for development of various neoplasm; MDM2 SNP309, a single-nucleotide T to G polymorphism located in the MDM2 gene promoter, has been reported to correlate with cancer risk and outcome, but results, of published studies and subsequent meta-analyses, about this association remains contradictory [10–14].