Association between vascular endothelial growth factor (VEGF) expression and tumor angiogenesis in ameloblastomas.
BACKGROUND
Expression of vascular endothelial growth factor (VEGF), a major angiogenic factor, and microvessel density (MVD), assessed by the use of anti-CD34 antibody, were immunohistochemically examined in benign and malignant ameloblastomas, as well as tooth germs, to clarify the possible role of angiogenesis in epithelial odontogenic tumors.


METHODS
Specimens of 5 tooth germs, 35 benign ameloblastomas and 5 malignant ameloblastomas were examined by immunohistochemistry using anti-VEGF and CD34 monoclonal antibodies.


RESULTS
Immunoreactivity for VEGF was detected in both normal and neoplastic odontogenic epithelial cells, and weakly in microvessels near odontogenic epithelial cells, suggesting that this angiogenic factor acts on endothelial cells via a paracrine mechanism in odontogenic tissues. Both benign and malignant ameloblastomas showed elevated VEGF expression as compared to tooth germs. VEGF expression was low in keratinizing cells in acanthomatous ameloblastomas and granular cells in granular cell ameloblastomas, and acanthomatous ameloblastomas showed the lowest VEGF reactivity among the subtypes of ameloblastomas. MVD in both benign and malignant ameloblastomas was higher than that in tooth germs, indicating increased demands for blood in the neoplastic tissues. CD34-positive microvessels in follicular ameloblastomas were numerous and small, whereas those in plexiform ameloblastomas were scattered and dilated. MVD tended to depend on VEGF expression levels in both benign and malignant ameloblastomas.


CONCLUSIONS
VEGF was considered to be an important mediator of angiogenesis in these epithelial odontogenic tumors, and up-regulation of VEGF might be associated with neoplastic or malignant changes of odontogenic epithelial cells.
Kumamoto
Hiroyuki
H
Division of Oral Pathology, Department of Oral Medicine and Bioregulation, Tohoku University Graduate School of Dentistry, Sendai, Japan. kumamoto@mail.cc.tohoku.ac.jp
Ohki
Kousuke
K
Ooya
Kiyoshi
K
D000564:Ameloblastoma / Q000098:blood supply* / Q000473:pathology; D000911:Antibodies, Monoclonal; D018952:Antigens, CD34 / Q000032:analysis; D003593:Cytoplasm / Q000648:ultrastructure; D003771:Dental Papilla / Q000098:blood supply; D016228:Endothelial Growth Factors / Q000032:analysis* / Q000235:genetics; D004730:Endothelium, Vascular / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008222:Lymphokines / Q000032:analysis* / Q000235:genetics; D008833:Microcirculation / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000473:pathology*; D019899:Paracrine Communication; D020033:Protein Isoforms / Q000032:analysis* / Q000235:genetics; D018709:Statistics, Nonparametric; D014083:Tooth Germ / Q000098:blood supply; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D000911:Antibodies, Monoclonal; D018952:Antigens, CD34; D016228:Endothelial Growth Factors; D008222:Lymphokines; D020033:Protein Isoforms; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors