Immunohistochemical detection of uPA, uPAR, PAI-1, and maspin in ameloblastic tumors.
BACKGROUND
To evaluate the roles of extracellular matrix (ECM)-degrading serine proteinase in progression of odontogenic tumors, expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1), and maspin was analyzed in ameloblastic tumors as well as in tooth germs.


METHODS
Tissue specimens of 10 tooth germs, 45 ameloblastomas, and 5 malignant ameloblastic tumors were examined immunohistochemically with the use of antibodies against uPA, uPAR, PAI-1, and maspin.


RESULTS
Immunohistochemical reactivity for uPA, uPAR, PAI-1, and maspin was detected in normal and neoplastic odontogenic tissues: uPA was recognized predominantly in mesenchymal cells, uPAR was evident in epithelial cells, PAI-1 was found in both epithelial and mesenchymal cells, and maspin was expressed only in epithelial cells. The levels of uPA and uPAR immunoreactivity in ameloblastic tumors were slightly higher than the levels in tooth germs, while PAI-1 reactivity in ameloblastomas tended to be lower than that in tooth germs. The level of maspin immunoreactivity in ameloblastomas was significantly higher than that in tooth germs, and ameloblastic carcinoma showed decreased maspin reactivity.


CONCLUSIONS
Expression of uPA, uPAR, PAI-1, and maspin in tooth germs and ameloblastic tumors suggests that interactions among these molecules contribute to ECM degradation and cell migration during tooth development and tumor progression. Altered expression of the serine proteinase and its associated molecules in ameloblastic tumors may be involved in oncogenesis of odontogenic epithelium.
Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan. kumamoto@mail.tains.tohoku.ac.jp
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D000564:Ameloblastoma / Q000473:pathology*; D002462:Cell Membrane / Q000473:pathology; D002465:Cell Movement / Q000502:physiology; D003593:Cytoplasm / Q000473:pathology; D003743:Dental Enamel / Q000473:pathology; D042783:Endothelial Cells / Q000473:pathology; D004792:Enzyme Precursors / Q000032:analysis*; D004847:Epithelial Cells / Q000473:pathology; D005109:Extracellular Matrix / Q000473:pathology; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008648:Mesoderm / Q000473:pathology; D009808:Odontogenic Tumors / Q000473:pathology; D017395:Plasminogen Activator Inhibitor 1 / Q000032:analysis*; D011956:Receptors, Cell Surface / Q000032:analysis*; D055293:Receptors, Urokinase Plasminogen Activator; D015842:Serine Proteinase Inhibitors / Q000032:analysis*; D015843:Serpins / Q000032:analysis*; D014083:Tooth Germ / Q000473:pathology; D014568:Urokinase-Type Plasminogen Activator / Q000032:analysis*
D004792:Enzyme Precursors; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; C085344:SERPIN-B5; D015842:Serine Proteinase Inhibitors; D015843:Serpins; D014568:Urokinase-Type Plasminogen Activator