HDAC-IN-32 is a potent HDAC inhibitor with IC 50 s of 5.2, 11, and 28 nM for HDAC1 , HDAC2 and HDAC6 , respectively. HDAC-IN-32 possesses potent antiproliferation activities against tumor cells. HDAC-IN-32 shows potent antitumor efficacy in vivo That trigger antitumor immunity.