IGF1R and Ewing sarcoma: Several of these Ewing sarcoma tumor cell–expressed genes have been previously studied in Ewing sarcoma [AXL, WNT5A, IGF-1R, TNFRSF10B (TRIAL-R2/DR5)], and have been described as potential targets in Ewing sarcoma and/or to be involved in Ewing sarcoma tumor cell migration/metastatic potential (53–57).