SUMO2 and synovial sarcoma: To systematically test the effect of SUMO2 inhibition on synovial sarcoma cell lines, we first evaluated the effect of TAK-981 on proliferation in four different human synovial sarcoma cell lines (SYO1, HS-SY-II, 1273/99, Aska-SS) as well as the epithelial squamous cell lung cancer cell line (SK-MES-I) and human embryonic kidney 293T cells (HEK-293T).