Immunohistochemical detection of insulin-like growth factors, platelet-derived growth factor, and their receptors in ameloblastic tumors.
BACKGROUND
To evaluate the roles of growth factors in oncogenesis and cytodifferentiation of odontogenic tumors, expression of insulin-like growth factors (IGFs), platelet-derived growth factor (PDGF), and their receptors was analyzed in ameloblastic tumors as well as in tooth germs.


METHODS
Tissue specimens of 10 tooth germs, 47 ameloblastomas, and five malignant ameloblastic tumors were examined immunohistochemically with the use of antibodies against IGF-I, IGF-II, IGF-I receptor (IGF-IR), PDGF A-chain, PDGF B-chain, PDGF alpha-receptor, and PDGF beta-receptor.


RESULTS
Immunohistochemical reactivity for IGFs, PDGF chains, and their receptors was detected predominantly in odontogenic epithelial cells near the basement membrane in tooth germs and in benign and malignant ameloblastic tumors. The expression levels of IGF-II and PDGF chains were significantly higher in ameloblastic tumors than in tooth germs. Malignant ameloblastic tumors showed higher reactivity for PDGF chains than benign ameloblastomas and higher reactivity for platelet-derived growth factor receptors than tooth germs. The expression levels of PDGF chains were significantly higher in follicular ameloblastomas than in plexiform ameloblastomas. Desmoplastic ameloblastomas showed higher expression of IGFs and IGF-IR when compared with other ameloblastoma subtypes.


CONCLUSIONS
Expression of IGFs, PDGF, and their receptors in tooth germs and ameloblastic tumors suggests that these growth factor signals contribute to cell proliferation or survival in both normal and neoplastic odontogenic tissues. Expression of these molecules in odontogenic tissues possibly affects interactions with the bone microenvironment during tooth development and intraosseous progression of ameloblastic tumors. Altered expression of the ligands and receptors in ameloblastic tumors may be involved in oncogenesis, malignant potential, and tumor cell differentiation.
Kumamoto
H
H
Division of Oral Pathology, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan. kumamoto@mail.tains.tohoku.ac.jp
Ooya
K
K
D000564:Ameloblastoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D049109:Cell Proliferation; D006801:Humans; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis*; D007573:Jaw Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis*; D020574:Proto-Oncogene Proteins c-sis / Q000096:biosynthesis; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000096:biosynthesis; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000096:biosynthesis; D017479:Receptors, Platelet-Derived Growth Factor / Q000096:biosynthesis; D017451:Receptors, Somatomedin / Q000096:biosynthesis; D014083:Tooth Germ / Q000378:metabolism*; D015854:Up-Regulation
D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D017451:Receptors, Somatomedin; C075278:platelet-derived growth factor A; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D020796:Receptor, Platelet-Derived Growth Factor alpha; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor