Up to 12% of high-grade osteosarcomas have amplification of the MDM2 gene at 12q13-15, but this is higher in low-grade central osteosarcoma and parosteal osteosarcoma, with around 29% and 67–79% MDM2 amplification, respectively [41, 51] (Table 2). The gene discussed is MDM2; the disease is osteosarcoma.