TP53 and neoplasm: A T-to-G single nucleotide polymorphism (SNP) is located 309 base pairs in promoter of MDM2, which known as MDM2 SNP309 (T > G), has been found to enhance the binding of the transcriptional activator specificity protein 1 (Sp1) to the P2 promoter of MDM2, resulting in an increased MDM2 transcription and MDM2 protein expression, and a weaken of the p53 tumor suppression function [7].