HDAC9 and neoplasm: The co-sorting of PBZ with other HDAC inhibitors for a number of gene signatures (Tables 1 and 2), and evidence of anti-proliferative effects on human tumor cell cultures (Figs 2 and 3, and Tables 3 and 4) prompted studies that demonstrated HDAC inhibitory activity with PBZ (Figs 4 and 5).