Genetic alterations supporting the genetic diagnosis were identified in four of the five patients (Fig. 1), including EWSR1-ATF1 in clear cell sarcoma, PTCH1-GLI1 in GLI1-rearranged tumor, SS18-SSX2 in synovial sarcoma, and SMARCA4-THOP1 in SMARCA4-deficient undifferentiated sarcoma. The gene discussed is EWSR1; the disease is undifferentiated (embryonal) sarcoma.