IDH1 and osteosarcoma: Indeed, multikinase inhibitors with a specific antiangiogenic activity in osteosarcoma [3,4,5], a novel inhibitor of transcriptional-promoting activity of ETS family transcription factors in sarcomas [6], and inhibitors of IDH1/2 activity in chondrosarcomas [7,8], have displayed some clinical benefits, but without exceeding a progression-free survival in the range of six months.