Co-expression of different angiogenic factors in external auditory canal cholesteatoma.
OBJECTIVE
Although external auditory canal cholesteatoma (EACC) was first described in 1850, its cause remains surprisingly unclear. Angiogenesis, the formation of new blood vessels, is essential to normal development and wound healing in adults. Abnormal regulation of angiogenesis has been implicated in the pathogenesis of several disorders. The aim of this study was to analyse angiogenesis regulator expression in EACC.


METHODS
Cryostat sections of 13 investigated EACC tissue samples and normal control tissue were immunostained for angiogenic hepatocyte growth factor (HGF)/scatter factor (SF), its c-Met receptor and vascular endothelial growth factor (VEGF) using a standard streptavidin-biotin complex procedure. Staining against von Willebrand factor (vWF) served as an endothelial marker. Statistical analysis was performed semiquantitatively.


RESULTS
The assayed angiogenic factors were all present in the EACC tissue, and partly overexpressed. vWF was detected in the apical layers of the matrix epithelium. Positive immunoreactivity for c-Met and VEGF was detectable in all layers of the EACC epithelium; however, adjacent tissue did not express c-Met and VEGE. HGF/SF was predominantly expressed in the adjacent perimatrix tissue and fibroblasts in particular were stained positive.


CONCLUSIONS
The presence of vWF in the apical part of the matrix depicted the attempt at angiogenesis in this part of the EACC. The detection of VEGF and c-Met in the epithelial part of the EACC implied that their origin may be epithelial, while HGF/SF may be secreted or stored in the adjacent mesenchymal EACC tissue. The angiogenic factors investigated seem to play an important role in establishing that EACC occurs by modulation of angiogenesis.
Naim
Ramin
R
Department of Otolaryngology, Head and Neck Surgery, University Hospital Mannheim, Mannheim, Germany. ramin.naim@hno.ma.uni-heidelberg.de
Riedel
Frank
F
Gotte
Karl
K
Bran
Gregor
G
Sadick
Haneen
H
Gossler
Ulrich
U
Hormann
Karl
K
D000328:Adult; D000368:Aged; D043925:Angiogenesis Inducing Agents / Q000378:metabolism*; D015415:Biomarkers; D016022:Case-Control Studies; D002781:Cholesteatoma / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D004424:Ear Canal / Q000098:blood supply / Q000473:pathology*; D004427:Ear Diseases / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D005260:Female; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D043925:Angiogenesis Inducing Agents; D015415:Biomarkers; D042461:Vascular Endothelial Growth Factor A; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met