Expression of endothelial cell-specific receptor tyrosine kinases and growth factors in human brain tumors.
Key growth factor-receptor interactions involved in angiogenesis are possible targets for therapy of CNS tumors. Vascular endothelial growth factor (VEGF) is a highly specific endothelial cell mitogen that has been shown to stimulate angiogenesis, a requirement for solid tumor growth. The expression of VEGF, the closely related placental growth factor (PIGF), the newly cloned endothelial high affinity VEGF receptors KDR and FLT1, and the endothelial orphan receptors FLT4 and Tie were analyzed by in situ hybridization in normal human brain tissue and in the following CNS tumors: gliomas, grades II, III, IV; meningiomas, grades I and II; and melanoma metastases to the cerebrum. VEGF mRNA was up-regulated in the majority of low grade tumors studied and was highly expressed in cells of malignant gliomas. Significantly elevated levels of Tie, KDR, and FLT1 mRNAs, but not FLT4 mRNA, were observed in malignant tumor endothelia, as well as in endothelia of tissues directly adjacent to the tumor margin. In comparison, there was little or no receptor expression in normal brain vasculature. Our results are consistent with the hypothesis that these endothelial receptors are induced during tumor progression and may play a role in tumor angiogenesis.
Department of Pathology, University of Helsinki, Finland.
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E
Hatva
A
A
Kaipainen
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P
Mentula
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J
Jääskeläinen
A
A
Paetau
M
M
Haltia
K
K
Alitalo
D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000737:chemistry / Q000201:enzymology* / Q000556:secondary; D002648:Child; D016228:Endothelial Growth Factors / Q000032:analysis*; D005260:Female; D005910:Glioma / Q000737:chemistry / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008222:Lymphokines / Q000032:analysis*; D008297:Male; D008545:Melanoma / Q000737:chemistry / Q000201:enzymology* / Q000556:secondary; D008579:Meningioma / Q000737:chemistry / Q000201:enzymology*; D008875:Middle Aged; D000072483:Placenta Growth Factor; D011257:Pregnancy Proteins / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis*; D017978:Receptors, Growth Factor / Q000032:analysis; D040262:Receptors, Vascular Endothelial Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; C000608036:PGF protein, human; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D000072483:Placenta Growth Factor; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor