EWSR1 and sarcoma: Except for sarcomas possessing the tumor-specific chromosomal translocations that form the specific gene fusions such as Ewing sarcoma with EWS-FLI1 fusion gene, the genetic loci involved in sarcomagenesis have not yet been fully elucidated, even though numerous genetic changes have been reported in many kinds of sarcomas including osteosarcoma and MFH.