HDAC9 and synovial sarcoma: To investigate if the SS18-SSX/TLE1 complex disruption induced by HDAC inhibitors can be detected in situ using the PLA method, SYO-1 synovial sarcoma cells were treated at IC50 doses with the class I HDAC inhibitors FK288 (romidepsin), MS275 (entinostat), SAHA (vorinostat) or the pan-HDAC inhibitor SB939 (pracinostat), as well as nexturastat A (a cytoplasmic class IIb HDAC6 inhibitor).