In this setting, a study performed on MDM2-amplified well-differentiated or dedifferentiated liposarcomas (LS), which are consistently characterized by a high-level genomic amplification (frequently >15-30 copies as clusters) of sequences derived from chromosomal region 12q13-15 comprising the oncogenes MDM2 and CDK4, showed that treatment with the MDM2 antagonist RG7112 activates the p53 pathway and decreases cell proliferation [6]. This evidence concerns the gene MDM2 and Leigh syndrome.