IGF1R and rhabdomyosarcoma: Given that MET was not active or expressed at substantial levels in Ewing sarcoma (Figure S2), we had included MET-driven rhabdomyosarcoma cell lines into this study [25], hypothesizing that rhabdomyosarcomas would utilize compensatory MET signaling and therefore be less amenable to RON and IGF1R co-targeting than Ewing sarcoma.