title: Claudin-1, but not claudin-4, exhibits differential expression patterns between well- to moderately-differentiated and poorly-differentiated gastric adenocarcinoma.
abstract: Claudins are members of a large family of transmembrane proteins, which are essential in the formation of tight junctions and have previously been associated with the process of tumor progression. Studies have reported the aberrant expression of claudin-1 and claudin-4 in numerous types of cancer. The present study aimed to investigate the expression of claudin-1 and claudin-4 in gastric adenocarcinoma tissue. Surgically resected gastric adenocarcinoma tissue specimens were obtained from 94 patients. Protein expression levels of claudin-1 and claudin-4 were determined using immunohistochemical staining; the association between claudin-1 or claudin-4 expression and various clinicopathological parameters were then analyzed. In gastric adenocarcinoma specimens, the expression rates of claudin-1 and claudin-4 were 43.6 and 87.2%, respectively. Claudin-1 expression demonstrated a significant correlation with histological type (P<0.01) and was significantly higher in well- to moderately-differentiated gastric adenocarcinomas compared with poorly-differentiated tumors. However, no correlation was observed between claudin-4 expression in adenocarcinoma and clinicopathological parameters. In conclusion, downregulation of claudin-1 expression in poorly-differentiated gastric adenocarcinoma may be involved in the biological transformation of tumors. The present findings suggested that claudin-1 may be an important protein associated with histological type and therefore may have potential for use as a prognostic marker for gastric adenocarcinoma. Further studies are required to elucidate the precise mechanism of claudin expression and its involvement in tumor progression.
authors.affiliation: Laboratory of Pathology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa 761-0123, Japan ; Group of Neurobiology, Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Tokuhara
authors.affiliation: Laboratory of Pathology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa 761-0123, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Morinishi
authors.affiliation: Department of Diagnostic Pathology, University Hospital, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Matsunaga
authors.affiliation: Department of Medical Technology, Ehime Prefectural University of Health Sciences, Ehime 791-2101, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohsaki
authors.affiliation: Department of Diagnostic Pathology, University Hospital, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kushida
authors.affiliation: Department of Diagnostic Pathology, University Hospital, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan.
authors.forename: Reiji
authors.initials: R
authors.lastname: Haba
authors.affiliation: Laboratory of Pathology, Department of Medical Technology, Kagawa Prefectural University of Health Sciences, Kagawa 761-0123, Japan.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Hirakawa
keywords: claudin-1; claudin-4; gastric adenocarcinoma; poorly differentiated; well to moderately differentiated