The impact that Mdm2SNP309G has on cancer risk is supported by the findings that patients diagnosed with Li-Fraumeni syndrome (LFS), a syndrome resulting from inherited germline mutations in p53, that are also homozygous for the Mdm2SNP309G allele develop tumors significantly earlier than patients with LFS lacking this polymorphism [6, 12]. This evidence concerns the gene TP53 and Li-Fraumeni syndrome.