HDAC9 and pancreatic neoplasm: Given the previous studies demonstrating the crucial role of HDAC7 as regulator in the thymocyte negative selection process through the down-regulating of the Nur77 gene expression, an orphan nuclear receptor involved in antigen-induced apoptosis of thymocytes [35], we though it would be interesting to determine the pattern of Nur77 gene expression simultaneously with those encoding HDAC and SIRTs in pancreatic tumor tissues.