FLI1 and Ewing sarcoma: Up to 90% of Ewing’s sarcoma cases result from reciprocal chromosomal translocation involving the EWSR1 (EWS) gene, which encodes an RNA-binding protein, and the gene encoding Friend leukemia virus integration 1 (FLI1), a member of the E26 transformation-specific (ETS) family of transcription factors, generating the pathognomonic EWS-FLI1 chimeric fusion protein.