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Virchows Arch. 2008 May;452(5):535-44. doi: 10.1007/s00428-008-0578-9.

Presence of HIF-1 and related genes in normal mucosa, adenomas and carcinomas of the colorectum.

Author information

1
Department of Pathology, VU University Medical Centre, PO Box 7057, 1007 MB Amsterdam, The Netherlands.

Abstract

Expression of the transcription factor hypoxia-inducible factor 1 (HIF-1), which plays a key role in cellular adaptation to hypoxia, was investigated in normal colorectal mucosa (ten), adenomas (61), and carcinomas (23). Tissue samples were analyzed for HIF-1 alpha, its upstream regulators, von Hippel-Lindau factor, AKT, and mammalian target of rapamycin (mTOR) and its downstream targets glucose transporter 1 (GLUT1), carbonic anhydrase IX, stromal-cell-derived factor 1 (SDF-1) by immunohistochemistry. In normal colorectal mucosa, HIF-1 alpha was observed in almost all nuclei of surface epithelial cells, probably secondary to a gradient of oxygenation, as indicated by pimonidazole staining. The same staining pattern was present in 87% of adenomas. In carcinomas, HIF-1 alpha was present predominantly around areas of necrosis (78%). Active AKT and mTOR, were present in all adenomas, carcinomas, and in normal colorectal mucosa. GLUT1 and SDF-1 were present in the normal surface epithelium of all adenoma cases, whereas in the carcinoma GLUT1 was located around necrotic regions and SDF-1 was present in all epithelial cells. In conclusion, HIF-1 alpha appears to be physiologically expressed in the upper part of the colorectal mucosa. The present observations support that upregulation of HIF-1 alpha and its downstream targets GLUT1 and SDF-1 in colorectal adenomas and carcinomas may be due to hypoxia, in close interaction with an active phosphatidylinositol 3-kinases-AKT-mTOR pathway.

PMID:
18351386
PMCID:
PMC2329727
DOI:
10.1007/s00428-008-0578-9
[Indexed for MEDLINE]
Free PMC Article

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