ETV6 and Ewing sarcoma: ETV6 was not defined as a gene regulated by EWS–FLI in 18 of 19 gene sets (Supplementary Table 4) and did not exhibit a unique pattern of expression in cell lines (Fig. 1a) or in primary tumours45 (Extended Data Fig. 1d and Supplementary Table 5) of Ewing sarcoma.