Genetically, these tumors lack the molecular hallmark of EWS, the Ewing sarcoma breakpoint region 1- avian Erythroblastosis virus Transforming sequence (EWSR1-ETS) fusion and include four distinct entities: Capicua (CIC)- and BCL6 corepressor (BCOR)-rearranged sarcomas, EWSR1-non-ETS sarcomas, and unclassified undifferentiated round cell sarcomas. This evidence concerns the gene BCOR and sarcoma.