IGF1R is broadly expressed in a number of pediatric solid tumors, and biological rationale existed for considering it a priority therapeutic target for cancers like Ewing sarcoma (Kurmasheva et al., 2009; Kurmasheva & Houghton, 2006; Scotlandi et al., 1998; Scotlandi et al., 2002), rhabdomyosarcoma (Bid, Zhan, Phelps, Kurmasheva, & Houghton, 2012; Thimmaiah et al., 2003; Zhan, Shapiro, & Helman, 1994), neuroblastoma (El-Badry et al., 1991; Misawa et al., 2000), and other childhood cancers. This evidence concerns the gene IGF1R and Ewing sarcoma.