Expression of bone morphogenetic proteins and their associated molecules in ameloblastomas and adenomatoid odontogenic tumors.
OBJECTIVE
To further clarify the roles of regulators of embryonic development, bone morphogenetic protein (BMPs) and their associated molecules, in oncogenesis and cytodifferentiation of odontogenic tumors, the expression of these regulator molecules were analyzed in epithelial odontogenic tumors as well as in tooth germs.


METHODS
Tooth germs, ameloblastomas, adenomatoid odontogenic tumors, and malignant ameloblastomas were examined by RT-PCR and immunohistochemistry for detection of BMP-2, -4, -7, BMP receptors I and II (BMPR-I, BMPR-II), core-binding factor alpha1 (CBFA1), and osterix.


RESULTS
mRNA expression of BMPs, BMPRs, CBFA1, and osterix was detected in all odontogenic tissues. Immunohistochemical reactivity for BMPs, BMPRs, and CBFA1 was detected in both epithelial and mesenchymal cells of tooth germs and epithelial odontogenic tumors. BMPs and BMPRs were evidently expressed in odontogenic epithelial cells in tooth germs and epithelial odontogenic tumors. Acanthomatous ameloblastomas showed increased BMP-7 reactivity in keratinizing cells. Nuclear CBFA1 expression was detected scatteredly in odontogenic epithelial cells in normal and neoplastic odontogenic tissues, as well as in some mesenchymal cells in tooth germs and in some stromal cells in epithelial odontogenic tumors. Ameloblastic carcinomas showed low reactivity for BMPs, BMPRs, and CBFA1.


CONCLUSIONS
BMPs and their associated molecules might play a role in cytodifferentiation of normal and neoplastic odontogenic epithelium via epithelial-mesenchymal interactions.
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*; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000032:analysis; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000032:analysis; D019485:Bone Morphogenetic Proteins / Q000032:analysis*; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000648:ultrastructure; D002471:Cell Transformation, Neoplastic / Q000473:pathology; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D004847:Epithelial Cells / Q000473:pathology; D004848:Epithelium / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008648:Mesoderm / Q000473:pathology; D009808:Odontogenic Tumors / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000076182:Sp7 Transcription Factor; D017154:Stromal Cells / Q000473:pathology; D014083:Tooth Germ / Q000473:pathology; D014157:Transcription Factors / Q000032:analysis; D016212:Transforming Growth Factor beta / Q000032:analysis
C525718:BMP2 protein, human; C525809:BMP4 protein, human; C525819:BMP7 protein, human; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D050659:Core Binding Factor Alpha 1 Subunit; D000076182:Sp7 Transcription Factor; C478163:SP7 protein, human; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II