HDAC9 and cancer: The adverse effects of non-selective HDAC inhibitors limit their therapeutic applicability beyond cancer therapy (Meier and Wagner, 2014). In this regard, MS-275 being a more selective HDAC inhibitor was better tolerated as monotherapy or when combined with the other forms of cancer therapy in clinical trials for solid tumors and hematological malignancies (Connolly et al., 2017).