FLT1 and Ewing sarcoma: As expected, copy number amplification of MYCN was detected in the KELLY and IMR-32 neuroblastoma models as were characteristic gene rearrangements in alveolar rhabdomyosarcoma (aRMS) (PAX3-FOXO1) and Ewing sarcoma (EWS-FLT1) models (Supplementary Table 4).