Immunohistochemical comparison of ki-67 expression in epithelial cell proliferation among variants of ameloblastomas

Introduction: Ameloblastoma has a diverse clinicopathological appearance. Several treatment modalities have been implicated based on such morphology. In this study we are evaluating cell proliferative marker Ki-67 in various histological and clinical subtypes of ameloblastomas.
Background: The primary aim of the study is to know the behaviour of various clinicopathological variants of ameloblastomas on the basis of Ki-67 expression in its epithelial cell proliferation.
Methods: Most common variants of ameloblastomas(n=20) consisting six follicular ameloblastomas(FA), six plexiform ameloblastomas(PA), two granular cell ameloblastomas(GCA) and six unicystic ameloblastomas(UA) with luminal proliferation were selected and examined morphologically and immunohistochemically for changes in proliferative activity using Ki-67 markers.
Results: The Ki-67 labelling index was significantly higher in FA,PA,UA than GCA. But ki-67marker mean labelling index difference was insignificant among FA,PA,and UA. Among various histopathological variants highest ki-67 mean labeling index was observed for unicystic ameloblastoma(46%) followed by plexiform(37.73%) and follicular ameloblastoma(37.6%) and was minimal in granular cell ameloblastoma(7.8%).
The pearson correlation (which is significant at the 0.01 level) for ki-67 expression was insignificant.(.977)among FA,PA,UA and GCA.
Conclusion: The pattern of expression of ki-67 varies among variants of ameloblastomas so it clearly indicates that it is not fruitful to compare ki-67 marker in ameloblastomas despite it is useful to assess the neoplastic behavior and recurrence of ameloblastomas. Also it can be concluded that histopathological variants have no or little role in assessing the behavior and prognosis and all ameloblastomas should be assessed clinically for treatment modalities.