Incorporation of SS18-SSX into BAF complexes causes biochemical changes, such as destabilization of the SMARCB1 (BAF47) subunit, and results in de novo BAF complex targeting to a highly cancer-specific set of sites, particularly broad, polycomb-repressed regions at which polycomb complex occupancy is reduced and gene expression is activated15,21. The gene discussed is SMARCB1; the disease is cancer.