FLI1 and peripheral primitive neuroectodermal tumor: The fusion transcript EWSR1/FLI1 is present in more than 90 % of the Ewing sarcomas, and in the related group of peripheral primitive neuroectodermal tumor (pPNET) [23], in rhabdomyosarcoma [24], in neuroblastoma [25] and in giant cell tumor of bone [26].