Evaluation of SOX9 expression in pancreatic ductal adenocarcinoma and intraductal papillary mucinous neoplasm.

OBJECTIVES Sex-determining region Y (SRY) box 9 (SOX9) is an important transcription factor required for development and has been implicated in several types of cancer. Sex-determining region Y box 9 has never been linked to pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasm (IPMN) of the pancreas. The aim of this study was to investigate the relationship between SOX9 and PDAC and that between SOX9 and IPMN. METHODS Surgical specimens were obtained from 55 patients with PDAC and 68 patients with IPMN and were investigated using SOX9 immunohistochemical analysis. RESULTS The rate of SOX9 positive cells to total pancreatic duct epithelial cells in a normal pancreas was 82.7%. On the other hand, the SOX9 positive rate in PDAC was 0.8%. There was a significant difference between the normal pancreas and PDAC (P = 0.0002). In IPMN, the SOX9 positive rate gradually decreased according to tumor progression, with the following rates observed: intraductal papillary mucinous adenoma (66.3%); noninvasive intraductal papillary mucinous carcinoma (46.3%); minimally invasive intraductal papillary mucinous carcinoma (30.5%); and invasive carcinoma originating in intraductal papillary mucinous carcinoma (2.3%). There were significant differences between each group (P < 0.05). CONCLUSIONS Our data suggested that SOX9 might contribute to carcinogenesis in PDAC and IPMN.