Prior to conducting combination studies, we first assessed the single agent antiproliferative activity of the potent class I HDAC inhibitor, entinostat, in pancreatic cancer cells; 6 human pancreatic cancer cell lines (PANC-1, MIA PaCa-2, BxPC-3, CFPAC-1, SUIT2 and SUIT2 Clone 1) were treated with variable concentrations of entinostat (0-100μM) for 72 hours and cell viability was assessed by XTT assays. This evidence concerns the gene HDAC9 and pancreatic neoplasm.