title: The expression of claudin-1, claudin-2, claudin-3, and claudin-4 in gastric cancer tissue.
abstract: BACKGROUND
  The claudins (CLDNs) are a family of functional tight junction proteins, and are involved with the epithelial-to-mesenchymal transition (EMT). The claudin proteins have a significant influence on the biological behavior of tumor progression in several types of cancers. In this study, we aimed to evaluate the expression pattern of claudin-1, claudin-2, claudin-3, and claudin-4 in gastric cancer tissue.
  
  
  METHODS
  Tissue was obtained from surgically resected specimens of 72 patients who were diagnosed with gastric adenocarcinoma at a single institution. The expressions of claudin-1, claudin-2, claudin-3, and claudin-4 were determined by immunohistochemical staining with the ABC method.
  
  
  RESULTS
  Claudin-2 demonstrated the highest expression rate (73.6%) and claudin-4 demonstrated the lowest expression rate (44.4%). The expression of claudin-1 was significantly lower in cases of intestinal type adenocarcinoma based on the Lauren classification. The expressions of claudin-3 and claudin-4 were significantly lower in cases with positive lymphatic invasion. The expression of claudin-3 was significantly lower in cases with an advanced T-stage (T3 and T4). The expression of claudin-3 showed significantly positive correlations with the expression of the other claudin proteins. In survival analysis, the expression of claudin-4 was related to good overall survival rate with significance (P = 0.046).
  
  
  CONCLUSIONS
  We suggest that claudin-3 and claudin-4 represent useful molecular markers for gastric cancer. Claudin-3 and claudin-4 would be the most important proteins related to the lymphatic invasion process, and claudin-4 would be useful with prognostic marker based on our results. Further investigations with a greater number of subjects are required to identify the action mechanism of claudin in gastric cancer.
authors.affiliation: Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hun
authors.initials: H
authors.lastname: Jung
authors.forename: Kyong Hwa
authors.initials: KH
authors.lastname: Jun
authors.forename: Ji Han
authors.initials: JH
authors.lastname: Jung
authors.forename: Hyung Min
authors.initials: HM
authors.lastname: Chin
authors.forename: Woo Bae
authors.initials: WB
authors.lastname: Park
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D062445:Claudin-1; D062465:Claudin-3; D062506:Claudin-4; D057167:Claudins; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; C568108:CLDN1 protein, human; C491875:CLDN2 protein, human; C568122:CLDN3 protein, human; C568157:CLDN4 protein, human; D062445:Claudin-1; D062465:Claudin-3; D062506:Claudin-4; D057167:Claudins; D008565:Membrane Proteins