There are several lines of evidence that support a link between EWS-FLI1 and IGF-1/IGF1-R signalling [42, 43] also in one of the putative progenitor cell of ESFT [44], and inhibition of this signaling pathway reduces tumor growth in vitro [45] and in vivo [54], blocks angiogenesis [55], induces cell death [61], and increases chemosensitivity [100]. This evidence concerns the gene EWSR1 and neoplasm.