Detection of Notch signaling molecules in ameloblastomas.
BACKGROUND
To evaluate the roles of Notch signaling in the oncogenesis and cytodifferentiation of odontogenic tumors, expression of Notch receptors and ligands was analyzed in ameloblastomas as well as in tooth germs.


METHODS
Tissue specimens of nine tooth germs and 32 ameloblastomas were examined by reverse transcriptase polymerase chain reaction and by in situ hybridization to determine the expression of Notch1, Notch2, Notch3, Delta1, and Jagged1.


RESULTS
mRNA expression of Notch1, Notch2, Notch3, Delta1, and Jagged1 was detected in all samples of normal and neoplastic odontogenic tissues. In tooth germs, Notch receptors were expressed in odontogenic epithelium (except for inner enamel epithelium), and expression of Notch ligands was lower in inner enamel epithelium than in other epithelial components. Odontogenic mesenchymal components were weakly reactive with these Notch signaling molecules. Ameloblastomas showed expression of Notch receptors and ligands in central polyhedral neoplastic cells. Notch2, Delta1, and Jagged1 were expressed in some neoplastic cells neighboring the basement membrane. Expression of Notch receptors and ligands was not found in keratinizing cells or granular cells in ameloblastoma variants. Stromal cells were weakly reactive with these Notch signaling molecules.


CONCLUSIONS
Expression of Notch receptors and ligands in tooth germs and ameloblastomas suggests that Notch signaling might control cell differentiation and proliferation of normal and neoplastic odontogenic epithelium.
Kumamoto
Hiroyuki
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
Ohki
Kousuke
K
D000564:Ameloblastoma / Q000737:chemistry*; D006801:Humans; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis*; D007573:Jaw Neoplasms / Q000737:chemistry*; D012333:RNA, Messenger / Q000032:analysis; D051880:Receptors, Notch / Q000032:analysis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014083:Tooth Germ / Q000737:chemistry*
D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D051880:Receptors, Notch