We thank B.D. Crompton and K. Stegmaier for sharing their RNA-Seq EwS tumor data sets, B. Schäfer for the EWS:FLI1 expressing plasmid, A.M. El-Naggar for mouse xenograft and K. Specht and K. Steiger for EwS tumor sections. The gene discussed is EWSR1; the disease is neoplasm.