For example, in Le Guellec et al. [3] reported that tumors that would otherwise be classified as pleomorphic undifferentiated sarcoma, but that demonstrated MDM2 amplification, had similar clinical characteristics, morphology, genomic profile, and outcome to conventional dedifferentiated liposarcoma and were significantly less aggressive than pleomorphic undifferentiated sarcomas without MDM2 amplification. The gene discussed is MDM2; the disease is undifferentiated (embryonal) sarcoma.