Ewing Sarcoma: Practice Essentials, Etiology, Epidemiology

Translocation of EWSR1 (Ewing sarcoma breakpoint region 1) with an ETS (E26 transformation-specific) transcription factor gene occurs in more than 95% of Ewing sarcomas. (Some argue that without a translocation, the tumor does not belong to Ewing sarcoma). The most common translocation seen in about 85% of all Ewing tumor is the t(11;22) translocation.

https://emedicine.medscape.com/article/990378-overview