title: Low expression of claudin-1 and presence of poorly-differentiated tumor clusters correlate with poor prognosis in colorectal cancer.
abstract: BACKGROUND
  Claudins are integral membrane proteins that constitute tight junctions. The aim of this study was to determine the clinical significance of claudin-1 in terms of the cell-cell adhesion, considering the poorly-differentiated tumor component.
  
  
  METHODS
  A total of 344 cases of stage II and III colorectal cancer were enrolled. We evaluated the expression of claudin-1 by immunohistochemistry and the extent of the poorly differentiated component.
  
  
  RESULTS
  Low expression of claudin-1 was associated with lymphatic involvement, histological differentiation, extent of poorly-differentiated component, reduced disease-free and overall survival. Multivariate analysis indicated that lymph node metastasis, venous involvement and low claudin-1 expression were independent predictors of recurrence, and that lymph node metastasis, venous involvement and low claudin-1 expression were associated with poor survival.
  
  
  CONCLUSIONS
  Our study not only showed the significance of low expression of claudin-1 as a predictor of poor prognosis of colorectal cancer but also supported the concept of grading of the poorly-differentiated component.
authors.affiliation: Osaka City University Graduate School of Medicine, Department of Surgical Oncology, 1-4-3 Asahi-machi Abeno-Ku, Osaka City, Osaka Prefecture, Japan, 545-8585.
authors.forename: Masatsune
authors.initials: M
authors.lastname: Shibutani
authors.forename: Eiji
authors.initials: E
authors.lastname: Noda
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Maeda
authors.forename: Hisashi
authors.initials: H
authors.lastname: Nagahara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohtani
authors.forename: Kosei
authors.initials: K
authors.lastname: Hirakawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002449:Cell Aggregation; D002454:Cell Differentiation; D062445:Claudin-1 / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis
chemical_list: C568108:CLDN1 protein, human; D062445:Claudin-1
keywords: Claudin; colorectal cancer; poorly-differentiated component; prognosis; recurrence