FLI1 and Ewing sarcoma: In addition to EWSR1-FLI1 expression in Ewing sarcoma, the EWSR1 gene fuses to various genes in other cancers (e.g., EWSR1/ELF5 in acute myeloid leukemia, EWSR1/NR4A3 in extraskeletal myxoid chondrosarcomas, and EWSR1/CHOP in liposarcoma etc) (Panagopoulos et al., 2002; Matsui et al., 2006; Filion et al., 2009; Endo et al., 2016; Panza et al., 2021).