Localization of endostatin in rat and human gliomas.
BACKGROUND
Endostatin is a potent inhibitor of endothelial cell proliferation, angiogenesis, and tumor growth. Its occurrence and localization has not yet been examined in human brain tumors. The authors report the production of a monoclonal antibody and detection of endostatin in rat and human gliomas by immunohistochemistry.


METHODS
The authors analyzed localization and tissue distribution of endostatin in 41 paraffin embedded glioma samples (18 glioblastoma multiforme, 7 WHO Grade III astrocytomas, 13 fibrillary, and 3 protoplasmic WHO Grade II astrocytomas) of human origin and 21 rat C6 gliomas by immunohistochemistry. Double labeling experiments confirmed the origin of endostatin-labeled cells.


RESULTS
Endostatin immunoreactivity was detected in tumor cells, endothelial cells, macrophages, and lymphocytes of both rat and human gliomas. The percentage of cells labeled with the endostatin antibody was significantly lower (P = 0.0126) in the tumor parenchyma of human glioblastomas than in WHO Grade II astrocytomas.


CONCLUSIONS
Endostatin was present in various cell types in rat and human gliomas in vivo. Lower levels in glioblastomas than in WHO Grade II astrocytomas might have reflected the shift of a probable regulatory balance between promoters and inhibitors of angiogenesis towards facilitation of neovascularization.
Institute of Brain Research, Medical School, University of Tuebingen, Germany. herwig.strik@med.uni-tueingen.de
H M
HM
Strik
H J
HJ
Schluesener
K
K
Seid
R
R
Meyermann
M H
MH
Deininger
D000328:Adult; D000368:Aged; D000818:Animals; D000911:Antibodies, Monoclonal; D001932:Brain Neoplasms / Q000098:blood supply / Q000473:pathology*; D003094:Collagen / Q000032:analysis*; D004195:Disease Models, Animal; D043169:Endostatins; D005260:Female; D005910:Glioma / Q000098:blood supply / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D010446:Peptide Fragments / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000911:Antibodies, Monoclonal; D043169:Endostatins; D010446:Peptide Fragments; D003094:Collagen