EWSR1 and Ewing sarcoma: EWS-FLI1 binds to DNA and interacts withthe transcriptional machinery by binding to multiple protein partners.The protein binding partners of EWS-FLI1 include RNA polymerase holozymeII, RNA helicase A (RHA), and CBP among others.221 The binding of EWS-FLI1 to RHA is thought to be a criticalstep in the development of Ewing’s Sarcoma.84,222 RHA has an important role in embryogenesis and is a transcriptionalcoactivator in tumorigenesis models.223 The N-terminal region of RHA is the site for binding of other proteinsforming essential functional complexes.