title: Hypoxia in relation to vasculature and proliferation in liver metastases in patients with colorectal cancer.
abstract: OBJECTIVE
  To investigate hypoxia measured by pimonidazole binding, glucose transporter 1 (GLUT1) and carbonic anhydrase IX (CA-IX) expression, proliferation, and vascularity in liver metastases of colorectal cancer and to compare GLUT1 and CA-IX expression in corresponding primary tumors.
  
  
  METHODS
  Twenty-five patients with liver metastases of colorectal cancer, planned for metastasectomy, were included. The hypoxia marker pimonidazole and proliferation marker iododeoxyuridine were administered before surgery. After immunofluorescent staining of the frozen metastases, pimonidazole binding, vascularity, and proliferation were analyzed quantitatively. Thirteen paraffin-embedded primary tumors were stained immunohistochemically for GLUT1 and CA-IX expression, which was analyzed semiquantitatively in primary tumors and corresponding liver metastases.
  
  
  RESULTS
  In liver metastases, pimonidazole binding showed a pattern consistent with diffusion-limited hypoxia. The mean pimonidazole-positive fraction was 0.146; the mean distance from vessels to pimonidazole-positive areas was 80 microm. When expressed, often co-localization was observed between pimonidazole binding and GLUT1 or CA-IX expression, but microregional areas of mismatch were also observed. No correlation between the level of pimonidazole binding and GLUT1 or CA-IX expression was observed. In some patients, a large fraction (up to 30%) of proliferating cells was present in pimonidazole-stained areas. Expression of CA-IX in primary tumors and metastases showed a significant correlation, which was absent for GLUT1 expression.
  
  
  CONCLUSIONS
  Compared with other tumor types, liver metastases of colorectal cancer contain large amounts of hypoxic cells. The lack of correlation with pimonidazole binding brings into question the value of GLUT1 and CA-IX as endogenous markers of hypoxia.
authors.affiliation: Department of Medical Oncology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands. h.vanlaarhoven@onco.umcn.nl
authors.forename: Hanneke W M
authors.initials: HW
authors.lastname: van Laarhoven
authors.forename: Johannes H A M
authors.initials: JH
authors.lastname: Kaanders
authors.forename: Jasper
authors.initials: J
authors.lastname: Lok
authors.forename: Wenny J M
authors.initials: WJ
authors.lastname: Peeters
authors.forename: Paul F J W
authors.initials: PF
authors.lastname: Rijken
authors.forename: Bastiaan
authors.initials: B
authors.lastname: Wiering
authors.forename: Theo J M
authors.initials: TJ
authors.lastname: Ruers
authors.forename: Cornelis J A
authors.initials: CJ
authors.lastname: Punt
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
authors.forename: Albert J
authors.initials: AJ
authors.lastname: van der Kogel
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002256:Carbonic Anhydrases / Q000378:metabolism*; D015687:Cell Hypoxia; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000378:metabolism*; D005260:Female; D051272:Glucose Transporter Type 1 / Q000378:metabolism*; D006801:Humans; D007065:Idoxuridine / Q000378:metabolism; D008113:Liver Neoplasms / Q000098:blood supply / Q000378:metabolism* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D009593:Nitroimidazoles / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D051272:Glucose Transporter Type 1; D009593:Nitroimidazoles; C033815:pimonidazole; D002256:Carbonic Anhydrases; D007065:Idoxuridine