EWSR1 and sarcoma: In this study, we show that the CIC-DUX4 fusion in EWSR1-fusion-negative sarcomas blocks IFNγ-induced ISG expression and the upregulation of MHC I. This fusion protein contains the terminal 98 amino acids of DUX4, aa327-424, that encompasses a region shown to be sufficient to suppress IFNγ signaling in the iDUX4-aa339-424 (see Figure 2C).