To identify key drivers of Ewing sarcoma identity, we investigated SEs based on H3K27ac ChIP-Seq profiles performed in a panel of 20 Ewing sarcoma cell lines, six primary Ewing sarcoma tumors, two Ewing sarcoma models derived from MSCs (MSC-EWSR1::FLI1), and six EWSR1::FLI1-silenced Ewing sarcoma cell lines (EWSR1::FLI1-KD)8,19,20,42,43. This evidence concerns the gene EWSR1 and Ewing sarcoma.