EWSR1 and Ewing sarcoma: ES is characterized by chromosomal translocation involving fusion of the 5’segment of the Ewing’s sarcoma breakpoint region 1 (EWS) gene to the 3’segment of an E26 transformation-specific (ETS) family gene with friend leukemia integration 1 transcription factor (FLI1) to generate EWS-FLI1 protein.