Disruption of Arid1a or Arid1b (both CBAF-specific) retains synovial sarcoma character, while Smarcb1 (PBAF- and CBAF-specific) or Pbrm1 (PBAF-specific) disruption does not, although all accelerate SS18::SSX-driven tumorigenesis in mice. The gene discussed is SMARCB1; the disease is synovial sarcoma.