EWSR1 and Ewing sarcoma: For instance, EWSR1 (Q01844), a EWS oncogene, may play a role in the tumorigenic process, causing Ewing sarcoma, a highly malignant, metastatic, primitive small round cell tumor of bone and soft tissue that affects children and adolescents (http://www.uniprot.org/uniprot/Q01844).