title: Prospective analysis of circulating endostatin levels in patients with renal cell carcinoma.
abstract: BACKGROUND
  The aim of the current study was to assess circulating levels of endogenous endostatin in patients with renal carcinoma and to determine the relationship of these levels to circulating levels of vascular endothelial growth factor (VEGF) and prognosis.
  
  
  METHODS
  The authors prospectively studied 66 patients (48 male, 18 female; mean age, 50 years) undergoing nephrectomy for renal carcinoma on clinical trials at the National Cancer Institute. Metastases were present in 51 of 66 patients (77%) at the time of nephrectomy. Preoperative and followup serum endostatin and VEGF levels were determined using competitive enzyme immunoassays and compared to a group of 32 age- and gender-matched healthy controls. Associations between circulating endostatin levels and clinicopathologic variables, including survival, were determined.
  
  
  RESULTS
  Preoperative endostatin levels were higher in renal carcinoma patients than in healthy controls (P = 0.05). There was a weak to moderate correlation between pretreatment serum endostatin levels and serum VEGF levels (r = 0.47; P = 0.001), and levels of both proteins increased significantly following nephrectomy (P < 0.0001 and P < 0.0001, respectively; n = 41). In addition, patients whose endostatin levels increased more than twofold after nephrectomy had significantly poorer prognoses than patients without such an increase (P = 0.018). This association was more pronounced when patients without metastases were excluded (P = 0.0037).
  
  
  CONCLUSIONS
  Circulating endostatin levels are elevated in patients with renal carcinoma and correlate with circulating VEGF levels. Endostatin levels increase after nephrectomy, and patients with the greatest increases experience shortened survival times. These findings suggest an association between tumor aggressiveness and the production of endogenous endostatin in patients with renal carcinoma.
mesh_terms: D000328:Adult; D000368:Aged; D020533:Angiogenesis Inhibitors / Q000097:blood*; D002292:Carcinoma, Renal Cell / Q000473:pathology* / Q000601:surgery; D003094:Collagen / Q000097:blood*; D043169:Endostatins; D016228:Endothelial Growth Factors / Q000097:blood; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery; D008222:Lymphokines / Q000097:blood; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D010446:Peptide Fragments / Q000097:blood*; D011379:Prognosis; D011446:Prospective Studies; D020033:Protein Isoforms; D016019:Survival Analysis; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D020533:Angiogenesis Inhibitors; D043169:Endostatins; D016228:Endothelial Growth Factors; D008222:Lymphokines; D010446:Peptide Fragments; D020033:Protein Isoforms; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D003094:Collagen