The pathogenesis of the vast majority of Ewing Sarcomas is driven by EWS/Ets fusion oncoproteins, which arise from recurrent chromosomal translocations and are necessary for tumorigenesis (Janknecht, 2005; Jedlicka, 2010; Toomey et al., 2010). This evidence concerns the gene EWSR1 and Ewing sarcoma.