EWSR1 and Ewing sarcoma: In immunocompromised mice, the expression of EWS-FLI1 in murine NIH-3T3 cells resulted in anchorage independent growth and accelerated tumorigenesis with a tumor phenotype reminiscent of human Ewing’s sarcoma.22 These observations support the notion that EWS-FLI1 can stimulate oncogenesis and it is to a large extent responsible for the histological characteristics associated with EFT.