EWSR1 and Ewing sarcoma: Other Ewing sarcoma cases are caused by alternative ETS protein fusions, including EWS‐ERG, EWS‐ETV1, EWS‐ETV4, EWS‐ETV5, EWS‐FEV, FUS‐FEV, and FUS‐ERG (Boone et al., 2021; Grunewald et al., 2018).