EWSR1 and Ewing sarcoma: Also, combination treatment of JQ1 with substances like YK-4-279 that directly binds to EWS-FLI1 and inhibits its oncogenic activity [45, 46] via blockade of specific protein interaction with factors important for mRNA splicing [47] and transcription [45] may result in synergistic effects on tumor growth and needs to be explored in preclinical models of ES.