Hypoxia in human colorectal adenocarcinoma: comparison between extrinsic and potential intrinsic hypoxia markers.
OBJECTIVE
To detect and quantify hypoxia in colorectal adenocarcinomas by use of pimonidazole and iododeoxyuridine (IdUrd) as extrinsic markers and carbonic anhydrase IX (CA IX), microvessel density (MVD), epidermal growth-factor receptor (EGFR), and vascular endothelial growth factor (VEGF) as intrinsic markers of hypoxia.


METHODS
Twenty patients with an adenocarcinoma of the left colon and rectum treated by primary surgery were injected with pimonidazole and IdUrd. Serial sections of tumor biopsies were single stained for VEGF, EGFR, Ki67, and double stained for blood vessels in combination with either pimonidazole, IdUrd, or CA IX. Percentage of expression was scored as well as colocalization of pimonidazole with CA IX.


RESULTS
The median percentage of hypoxia, as judged by pimonidazole staining, was 16.7% (range, 0-52.4%). The expression of pimonidazole correlated inversely with the total MVD and endothelial cord MVD (R = -0.55, p = 0.01; R = -0.47, p = 0.04). Good colocalization was found between pimonidazole and CA IX in only 30% of tumors, with no correlation overall between pimonidazole and CA IX, VEGF, or EGFR or between the different intrinsic markers. Cells around some vessels (0.08-11%) were negative for IdUrd but positive for Ki 67, which indicated their lack of perfusion at the time of injection.


CONCLUSIONS
Chronic and acute hypoxic regions are present in colorectal tumors, as shown by pimonidazole and IdUrd staining. Only in a minority of tumors did an association exist between the areas stained by pimonidazole and those positive for CA IX. Pimonidazole also did not correlate with expression of other putative intrinsic hypoxia markers (VEGF, EGFR).
Goethals
Laurence
L
Department of Radiation Oncology, University Hospital Gasthuisberg, Leuven, Belgium.
Debucquoy
Annelies
A
Perneel
Christiaan
C
Geboes
Karel
K
Ectors
Nadine
N
De Schutter
Harlinde
H
Penninckx
Freddy
F
McBride
William H
WH
Begg
Adrian C
AC
Haustermans
Karin M
KM
D000230:Adenocarcinoma / Q000098:blood supply / Q000737:chemistry / Q000503:physiopathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000032:analysis; D002256:Carbonic Anhydrases / Q000032:analysis; D015687:Cell Hypoxia; D003110:Colonic Neoplasms / Q000098:blood supply / Q000737:chemistry / Q000503:physiopathology*; D066246:ErbB Receptors / Q000032:analysis; D005260:Female; D006801:Humans; D007065:Idoxuridine / Q000493:pharmacokinetics; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009593:Nitroimidazoles / Q000493:pharmacokinetics; D015588:Observer Variation; D012004:Rectal Neoplasms / Q000098:blood supply / Q000737:chemistry / Q000503:physiopathology*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
D015415:Biomarkers; D009593:Nitroimidazoles; D042461:Vascular Endothelial Growth Factor A; C033815:pimonidazole; D066246:ErbB Receptors; D002256:Carbonic Anhydrases; D007065:Idoxuridine