title: Claudins as prognostic factors for renal cell cancer.
abstract: BACKGROUND
  Claudins are tight junction proteins and their expression is often different in normal and corresponding tumor cells. In the present study, we determined how the expression of claudins 1-5 and 7 correlated to survival, grade and stage of patients with renal cell cancer (RCC).
  
  
  METHODS
  Primary tumor samples were collected retrospectively from 229 RCC patients. Claudins were detected by immunohistochemistry using commercial monoclonal antibodies against claudins 1-5 and 7. Median survival time was 6.5 years confidence interval (CI) (4.5-8.5, n=224). Kaplan-Meier survival estimated method was used in survival analyses.
  
  
  RESULTS
  Positive expression was detected in 62%, 67%, 45%, 55%, 7% and 35% of cases for claudins 1, 2, 3, 4, 5 and 7, respectively. High expression of claudin 2 was observed in 20% of cases while high expression of other claudins was less frequent. Claudins were compared to classical prognostic factors. On cross-tabulation, claudin 1 (p<0.001) and claudin 2 (p=0.009) were significantly associated with lower-grade and higher-grade tumors, respectively. None of the claudins was significantly associated with tumor stage or patient survival.
  
  
  CONCLUSIONS
  Claudins 1 and 2 were associated with tumor grade. However, none of the claudins was a more powerful prognostic factor than tumor stage.
authors: University of Tampere, School of Medicine, Department of Anesthesia, Tampere University Hospital, Tampere, Finland juha.virman@uta.fi.
authors: Juha
authors: J
authors: Virman
authors: Department of Clinical Pathology and Forensic Medicine, University of Eastern Finland, Cancer Center of Eastern Finland, Kuopio, Finland.
authors: Ylermi
authors: Y
authors: Soini
authors: Department of Pathology, Tampere University Hospital, Tampere, Finland.
authors: Paula
authors: P
authors: Kujala
authors: Science Center, Pirkanmaa Hospital District and School of Health Sciences, University of Tampere, Tampere, Finland.
authors: Tiina
authors: T
authors: Luukkaala
authors: Department of Oncology, Tampere University Hospital, Tampere, Finland.
authors: Tapio
authors: T
authors: Salminen
authors: Department of Oncology, Tampere University Hospital, Tampere, Finland.
authors: Kaisa
authors: K
authors: Sunela
authors: University of Tampere, School of Medicine, Department of Anesthesia, Tampere University Hospital, Tampere, Finland Department of Oncology, Tampere University Hospital, Tampere, Finland.
authors: Pirkko-Liisa
authors: PL
authors: Kellokumpu-Lehtinen
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000737:chemistry / Q000401:mortality* / Q000473:pathology; D057167:Claudins / Q000032:analysis*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000737:chemistry / Q000401:mortality* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis
chemical_list: D057167:Claudins
keywords: Claudins; expression; prognostic factors; renal cell cancer (RCC)