EWSR1 and Ewing sarcoma: In the Ets-family, the interaction of EWS-FLI1, EWS-ERG and EWS-ETV1 fusion transcription factors (generated after chromosome translocation and associated with Ewing sarcomas) with the RNA helicase A is inhibited by the (S)-enantiomer of YK-4-279 (Figure 4D) [139,140].