The authors ChIP'ped the C-terminal portion of FLI1 gene in two Ewing sarcoma cell lines (A673 and SK-N-MC) and defined the 1785 peaks that are present in both cell lines as the ‘core set of EWS-FLI1’ binding sites (provided in the Supplementary Table S1 of the corresponding paper). Here, EWSR1 is linked to Ewing sarcoma.