WT1 and Ewing sarcoma: EWSR1 is fused to an ETS transcription factor (FLI-1, ERG, ETV-1, E1AF or FEV) in Ewing sarcoma; to activating transcription factor-1 (ATF-1) in soft tissue clear cell sarcoma; to Wilms Tumor -1 (WT1) in desmoplastic small round cell; to nuclear receptor 4A3 (NR4A3) in extraskeletal myxoid chondrosarcoma, and to C/EBP-homologous protein (CHOP) in myxoid liposarcoma [1].