In almost 90% of well- and dedifferentiated liposarcomas, an amplification of the 12q13-q22 gene region is present, as well as an overexpression of mouse double minute 2 homolog (MDM2) and cyclin dependent kinase 4 (CDK4), proteins characteristic of these liposarcoma subtypes [29]. The gene discussed is MDM2; the disease is liposarcoma.