We have recently shown that the MDM2 antagonist activates the TP53 pathway and decreases cell proliferation in patients with TP53-wild type and other solid tumors with or without MDM2 amplification, and that this was associated with long term disease in about 20% of sarcoma patients included in phase I trials and treated with nutlins [12, 13]. This evidence concerns the gene MDM2 and sarcoma.