HDAC9 and cholangiocarcinoma: 15, 16, 17, 18 Two HDAC inhibitors, SAHA and romidepsin, are US Food and Drug Administration (FDA) approved for the treatment of cutaneous T-cell lymphoma.19 MI192, a novel HDAC3-selective inhibitor, was found to be beneficial for rheumatoid arthritis in vitro with marginal toxicity.20 However, the effects of MI192 in CCA have not yet been studied.