title: Plasma concentrations of Ang-1, Ang-2 and Tie-2 in gastric cancer.
abstract: OBJECTIVE
  Ang-1 and Ang-2 have both been identified as ligands for Tie-2, a receptor expressed on endothelial cells (EC). They play critical roles in angiogenesis, in concert with VEGF. Ang-1-binding to Tie-2 maintains and stabilizes mature vessels by promoting interactions between EC and the surrounding extra-cellular matrix. However, Ang-2 shows context-dependent, proangiogenic and antiangiogenic activities. Despite the rapidly accumulating histopathological data reporting differences in the expression of members of the Ang family on the surface of various normal and tumour cells, data for these growth factors in plasma from cancer patients, including gastric cancer, remain scarce. The aims of the present study were to measure the plasma concentrations of Ang-1, Ang-2 and Tie-2 in gastric cancer patients, and to assess the correlation between the concentrations of these factors and the stage of the tumor.
  
  
  METHODS
  The study cohort consisted of 50 patients (33 male, 17 female) with gastric cancer, ranging in age from 38 to 74 years (mean age 55.3±12.4), and 50 sex- and age-matched, healthy controls. Determinations of Ang-1, Ang-2 and Tie-2 were performed using the enzyme-linked immunosorbent assay (ELISA) method.
  
  
  RESULTS
  Concentrations of Ang-2 and Tie-2 were significantly higher in patients with gastric cancer than controls, while concentrations of Ang-1 were not statistically different between the groups. Concentrations of Ang-1, Ang-2 and Tie-2 were not statistically significantly different in gastric cancer patients with different stages of disease.
  
  
  CONCLUSIONS
  Ang-2 and Tie-2 plasma concentrations might be useful, additional tumor markers in gastric cancer.
authors.affiliation: Karaelmas University, Department of Internal Medicine, Division of Medical Oncology, Zonguldak, Turkey. bulengin@yahoo.com
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Engin
authors.forename: Yücel
authors.initials: Y
authors.lastname: Ustündağ
authors.forename: Ishak
authors.initials: I
authors.lastname: Ozel Tekin
authors.forename: Ayla
authors.initials: A
authors.lastname: Gökmen
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D042683:Angiopoietin-1 / Q000097:blood; D042702:Angiopoietin-2 / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D042787:Receptor, TIE-2 / Q000097:blood*; D013274:Stomach Neoplasms / Q000097:blood*
chemical_list: D042683:Angiopoietin-1; D042702:Angiopoietin-2; D014408:Biomarkers, Tumor; D042787:Receptor, TIE-2