title: Caveolin 1 protein expression in renal cell carcinoma predicts survival.
abstract: BACKGROUND
  Caveolae play a significant role in disease phenotypes such as cancer, diabetes, bladder dysfunction, and muscular dystrophy. The aim of this study was to elucidate the caveolin-1 (CAV1) protein expression in renal cell cancer (RCC) and to determine its potential prognostic relevance.
  
  
  METHODS
  289 clear cell RCC tissue specimens were collected from patients undergoing surgery for renal tumors. Both cytoplasmic and membranous CAV1 expression were determined by immunohistochemistry and correlated with clinical variables. Survival analysis was carried out for 169 evaluable patients with a median follow up of 80.5 months (interquartile range (IQR), 24.5-131.7 months).
  
  
  RESULTS
  A high CAV1 expression in the tumor cell cytoplasm was significantly associated with male sex (p = 0.04), a positive nodal status (p = 0.04), and poor tumor differentiation (p = 0.04). In contrast, a higher than average (i.e. > median) CAV1 expression in tumor cell membranes was only linked to male sex (p = 0.03). Kaplan-Meier analysis disclosed significant differences in 5-year overall (51.4 vs. 75.2%, p = 0.001) and tumor specific survival (55.3 vs. 80.1%, p = 0.001) for patients with higher and lower than average cytoplasmic CAV1 expression levels, respectively. Applying multivariable Cox regression analysis a high CAV1 protein expression level in the tumor cell cytoplasm could be identified as an independent poor prognostic marker of both overall (p = 0.02) and tumor specific survival (p = 0.03) in clear cell RCC patients.
  
  
  CONCLUSIONS
  Over expression of caveolin-1 in the tumour cell cytoplasm predicts a poor prognosis of patients with clear cell RCC. CAV1 is likely to be a useful prognostic marker and may play an important role in tumour progression. Therefore, our data encourage further investigations to enlighten the role of CAV1 and its function as diagnostic and prognostic marker in serum and/or urine of RCC patients.
authors.affiliation: Department of Urology, Hannover Medical School, (Carl-Neuberg-Strasse 1), Hannover, (30625), Germany. steffens.sandra@mh-hannover.de
authors.forename: Sandra
authors.initials: S
authors.lastname: Steffens
authors.forename: Andres J
authors.initials: AJ
authors.lastname: Schrader
authors.forename: Hanna
authors.initials: H
authors.lastname: Blasig
authors.forename: Gesa
authors.initials: G
authors.lastname: Vetter
authors.forename: Hendrik
authors.initials: H
authors.lastname: Eggers
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Tränkenschuh
authors.forename: Markus A
authors.initials: MA
authors.lastname: Kuczyk
authors.forename: Jürgen
authors.initials: J
authors.lastname: Serth
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D002292:Carcinoma, Renal Cell / Q000097:blood* / Q000401:mortality*; D051242:Caveolin 1 / Q000097:blood*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D007680:Kidney Neoplasms / Q000097:blood* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000097:blood; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D051242:Caveolin 1; D009363:Neoplasm Proteins