FUS and neoplasm: Given the ability of EWSR1, FUS and TAF15 to induce phase-separated condensates33,34, and the critical role of their prion-like domains in establishing DNA accessibility and chromatin activation in other sarcomas21, our studies suggest that EWSR1-ATF1 may display similar neo-morphic pioneer properties enabling CCS tumor initiation, including the ability to selectively interact with the SWI/SNF remodeling complex.