The genetic alterations more frequently detected in sarcomas are: tyrosine-kinase activating mutations (9), gene fusions of growth factors or kinases (e.g., involving ALK, ROS1 or NTRK family) (10–12), gene fusions involving transcriptions factors (e.g., EWSR1-FLI1, PAX3-FOXO1) (13, 14), inactivation of tumor suppressor genes (e.g., NF1, PTEN or TP53) (15–17), gene amplification (e.g. MDM2 and MDM2/CDK4 co-amplification) (18) and epigenetic dysregulation (19, 20). The gene discussed is MDM2; the disease is sarcoma.