Abstract
To investigate the roles of autophagy-related molecules in odontogenic tumors, we analyzed the expression of Beclin1 and ATG5 in tissue specimens of 11 tooth germs, 41 ameloblastomas, and 6 malignant ameloblastic tumors by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry. RT-PCR and Western blot analyses confirmed expression of Beclin1 and ATG5 in all samples of normal and neoplastic odontogenic tissues. Immunohistochemical reactivity for Beclin1 was evident in odontogenic epithelial cells neighboring the basement membrane in tooth germs, ameloblastomas, and metastasizing ameloblastomas. ATG5 reactivity was found in most epithelial components of tooth germs, while ameloblastomas and metastasizing ameloblastomas showed ATG5 expression in many peripheral and some central neoplastic cells. Immunoreactivity for Beclin1 and ATG5 was evident in granular neoplastic cells in granular cell ameloblastomas, and ameloblastic carcinomas and clear cell odontogenic carcinomas showed Beclin1 and ATG5 expression in most neoplastic cells. These findings suggest that autophagic cell death might contribute to cell kinetics in odontogenic tissues. The molecular machinery for autophagy is possibly involved in oncogenesis and cell differentiation of odontogenic epithelium.
