title: Plasminogen activator system, vascular endothelial growth factor, and colorectal cancer progression.
abstract: OBJECTIVE
  To plasminogen activator system (PAS) consists of the plasminogen activators (urokinase (uPA) and tissue-type (tPA) plasminogen activators), the uPA receptor (uPAR), and the plasminogen activator inhibitors (PAI-1 and PAI-2). Plasminogen activators activate plasminogen to plasmin, which can break down extracellular matrix (ECM) components. Vascular endothelial growth factor (VEGF) is a mitogen for endothelial cells and is involved in angiogenesis. VEGF has been shown to upregulate uPA and this may facilitate tumour angiogenesis further.
  
  
  METHODS
  PAS components and VEGF were determined by enzyme linked immunosorbent assay (ELISA) in paired colorectal tumour and normal tissue (n = 50) and correlated with pathological staging.
  
  
  RESULTS
  uPA, uPAR, PAI-1, and VEGF values were significantly higher in tumour tissue (for example, tumour uPA: median, 2.3 (range, 0.1-6.7) ng/mg protein v normal uPA: median, 0.2 (range, 0-2.6) ng/mg protein). tPA was significantly higher in normal mucosa and there was no difference in PAI-2. uPA, uPAR, PAI-1, and VEGF values significantly correlated with each other and with Dukes's staging (uPA in adenomas: median, 0.42 (range, 0.1-1.2) ng/mg protein; upA in Dukes's B tumours: median, 2.1 (range, 0.4-4.3) ng/mg protein; and uPA in Dukes's D tumours: median, 4.0 (range, 3.7-4.2) ng/mg protein) and lymphatic invasion. In addition PAI-1 also correlated with tumour size and differentiation.
  
  
  CONCLUSIONS
  The involvement of the PAS and VEGF in colorectal cancer appears to be complex. uPA, uPAR, PAI-1, and VEGF were upregulated in tumour tissue and this correlated with Dukes's staging and lymphatic invasion.
authors.affiliation: North Tees General Hospital, Stockton on Tees TS19 8PE, UK. drlizbaker@yahoo.co.uk
authors.forename: E A
authors.initials: EA
authors.lastname: Baker
authors.forename: F G
authors.initials: FG
authors.lastname: Bergin
authors.forename: D J
authors.initials: DJ
authors.lastname: Leaper
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D016228:Endothelial Growth Factors / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008222:Lymphokines / Q000378:metabolism*; D009367:Neoplasm Staging; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D017396:Plasminogen Activator Inhibitor 2 / Q000378:metabolism; D010960:Plasminogen Activators / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D010959:Tissue Plasminogen Activator / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D014408:Biomarkers, Tumor; D016228:Endothelial Growth Factors; D008222:Lymphokines; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; D017396:Plasminogen Activator Inhibitor 2; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator; D014568:Urokinase-Type Plasminogen Activator