A comparative immunohistochemical study of Ki-67 and Bcl-2 expression in solid ameloblastoma and adenomatoid odontogenic tumor

Abstract

Background: Solid ameloblastoma (SAB) is an invasive tumor which infiltrates adjacent normal tissues. Adenomatoid odontogenic tumor is a noninvasive tumor and never infiltrates surrounding normal tissues. The purpose of this study was to determine the biological behavior of these two epithelial odontogenic neoplasm by detecting Ki-67 and Bcl-2, which are mitotic and anti apoptotic markers respectively.

Materials and Methods: In this analytical retrospective study, 16 samples of SAB and 16 samples of adenomatoid odontogenic tumor were selected. The samples were deparafinized and antigens were retrieved. Immunohistochemistry technique was applied for evaluation of these two markers. Monoclonal antibodies MIB1 and Bcl-2 were used to detect Ki-67 and Bcl-2 protein respectively, then the labeling index (LI) was calculated for both markers according to cellular staining. Data were analyzed by “t” test, (P<0.05).

Results: The mean values of LI for Ki-67 in SAB and Adenomatiod odontogenic tumor (AOT) were 4 and 1% respectively and for Bcl-2 in SAB and AOT were 63 and 26% respectively. The indices of both markers were higher in SAB compared to AOT (P<0.05).

Conclusions: Higher percentage of these two markers in SAB compared to AOT confirms the aggressive behavior of SAB and the hamartomatosis behavior of AOT.

Key Words: Adenomatoid odontogenic tumor, ameloblastoma, Bcl-2 protein, immunohistochemistry, Ki-67 antigene