1. ¹Department of Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
2. ²Department of Biological Information, Tokyo Institute of Technology, Yokohama, Japan

Correspondence: Dr N Fukushima, MD, PhD, Department of Pathology, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan. E-mail: nfukushima-tky@umin.ac.jp

Received 4 November 2007; Revised 16 April 2008; Accepted 17 April 2008; Published online 16 May 2008.

Abstract

Desmoplasia is a common feature of infiltrating ductal adenocarcinoma of the pancreas. This process is intricately interacted between the host and neoplastic cells. Recently, by transcriptome analysis, periostin was identified as a significantly highly expressed gene in pancreatic stellate cells. To investigate the characteristics of periostin immunodeposition in pancreatic ductal neoplasms, we performed immunohistochemistry and in situ hybridization, focusing on tumor–stromal cells interactions. Eighty-one surgically resected pancreatic lesions, including 35 pancreatic ductal adenocarcinoma, 26 intraductal papillary-mucinous neoplasms, 11 mucinous cystic neoplasms and 9 chronic pancreatitis, were studied. In all ductal adenocarcinomas, periostin deposition was observed in the stroma around the infiltrating cancer on immunohistochemistry. Cellular stroma of mucinous cystic neoplasm, called 'ovarian-type' stroma, did not show periostin deposition. In chronic pancreatitis, most of the staining patterns of periostin were perilobular and meshwork-like. Periostin gene expression was detected solely in the stromal cells on in situ hybridization. Intraductal papillary-mucinous neoplasms were classified into four groups on the basis of the histological grade, namely, adenoma, non-invasive adenocarcinoma, adenocarcinoma with microscopical invasion and with macroscopically evident invasion. In intraductal papillary-mucinous neoplasm, periostin deposition in the periductal stroma increased in frequency and intensity in adenocarcinoma compared with adenomas (P=0.014). Furthermore, our results showed that a higher frequency of periostin deposition was correlated with a higher frequency of 'intestinal phenotype' of proliferating epithelium (P=0.036) and laminin-52 chain expression (P<0.001) in intraductal papillary-mucinous neoplasm, the latter of which is frequently expressed in invasive carcinoma. This is the first report to describe the periostin immunohistochemistry in intraductal papillary mucinous neoplasm of the pancreas.