CMap gene expression enrichment values for PBZ relative to HDAC inhibitors for a varied group of gene signatures (Table 2) greatly expanded the initial observation that co-sorted PBZ with HDAC inhibitors for a common gene expression signature resulting from the effects of SAHA, TSA and MS-275 in human breast cancer cells and human bladder cancer cells (Table 1) [19]. The gene discussed is HDAC9; the disease is breast cancer.