HDAC9 and Ewing sarcoma: Finally, recognizing that HDAC inhibitors target multiple pathways beyond DNA replication, we demonstrate that BRD4, a transcriptional cofactor for the EWS::FLI1 oncoprotein and a regulator of DNA replication, and survivin (BIRC5), an antiapoptotic protein, are also targets of HDAC inhibitors in Ewing sarcoma cells (41–45).