EWSR1 and Ewing sarcoma: Eighty-five percent of Ewing's sarcomas contain the t(11;22)(q24;q12) reciprocal chromosomal translocation, which results in the generation of a novel fusion protein combining the N-terminal transactivation domain of the Ewing's sarcoma breakpoint region 1 gene (EWSR1) and the C-terminal DNA binding domain of an ETS (E26 transformation-specific) family member gene [3], most commonly the FLI-1 (Friend leukemia integration 1) transcription factor gene.