HDAC9 and B-cell non-Hodgkin lymphoma: Entinostat, a class I HDAC inhibitor, decreases Bcl-XL levels and induces caspase-dependent/independent apoptosis in B-cell lymphomas (Frys et al., 2015), while entinostat induces caspase-dependent apoptosis in B-cell chronic lymphocytic leukemia cells (Lucas et al., 2004).