title: Raised endothelin 1 levels in patients with colorectal liver metastases.
abstract: BACKGROUND
  Endothelin 1 (ET-1), a vasoconstrictor peptide, has been implicated as a tumour growth stimulator and an angiogenesis factor.
  
  
  METHODS
  To assess the involvement of ET-1 in colorectal cancer, immunoelectron microscopy for ET-1 was performed in colorectal liver metastases and normal liver (n = 6). ET-1 plasma levels were measured by radioimmunoassay in patients with colorectal cancer, with (n = 18) and without (n = 12) liver metastases, and in controls (n = 22).
  
  
  RESULTS
  In normal liver, ET-1 was present in endothelial cells; in tumour, it was observed in endothelial cells, tumour cells and myofibroblasts. Mean(s.d.) plasma ET-1 levels were 2.75 (1.37) pg/ml in controls, 4.53(1.61) pg/ml in patients with colorectal liver metastases (P = 0.001) and 3.92(1.32) pg/ml in patients without metastases (P = 0.02).
  
  
  CONCLUSIONS
  ET-1 was present in various cell types within colorectal liver metastases and raised levels were found in the plasma of patients with colorectal cancer. ET-1 may not only modulate tumour vascular tone but also act on tumour growth and angiogenesis, both locally and systemically.
authors.affiliation: Department of Surgery, University College Medical School, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Shankar
authors.forename: M
authors.initials: M
authors.lastname: Loizidou
authors.forename: G
authors.initials: G
authors.lastname: Aliev
authors.forename: S
authors.initials: S
authors.lastname: Fredericks
authors.forename: D
authors.initials: D
authors.lastname: Holt
authors.forename: P B
authors.initials: PB
authors.lastname: Boulos
authors.forename: G
authors.initials: G
authors.lastname: Burnstock
authors.forename: I
authors.initials: I
authors.lastname: Taylor
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D015179:Colorectal Neoplasms / Q000378:metabolism*; D019332:Endothelin-1 / Q000097:blood*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D011863:Radioimmunoassay; D018180:Thrombomodulin / Q000097:blood
chemical_list: D014408:Biomarkers, Tumor; D019332:Endothelin-1; D018180:Thrombomodulin