IGF1R and Ewing sarcoma: Hirschfeld and Helman first described a role for IGF-1R in tumor promotion of pediatric solid tumors including osteosarcoma and Ewing's sarcoma (EWS), and since then, preclinical studies have confirmed that IGF-1R autocrine signaling is important for not only their pathogenesis but for a number of soft-tissue sarcomas as well [32].