Synovial sarcoma is a cancer driven by a fusion oncoprotein, SS18::SSX, that links SS18, a subunit of BAF-family chromatin remodeling complexes, to the carboxy terminus of SSX, which avidly binds nucleosomes with the histone post-translational modification H2AK119ub. This evidence concerns the gene BANF1 and synovial sarcoma.