However, reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed the presence of a rare variant of the EWSR1-FLI1 fusion transcript, featuring fusion of EWSR1 exon 10 to FLI1 exon 6.     ///    Primary subcutaneous spindle cell Ewing sarcoma with strong S100 expression and EWSR1-FLI1 fusion: a case report..     ///    "Ewing sarcoma most often is characterized by a fusion of the Ewing sarcoma breakpoint region 1 (EWSR1) and the Friend leukemia virus integration 1 (FLI1) genes, forming an EWSR1-FLI1 fusion transcript. "