Expression of Matrix Metalloproteinase-9 in Different Histopathological Variants of Ameloblastoma: A Cross-sectional Study

Abstract

Introduction: Ameloblastomas are benign and the most common odontogenic neoplasms with many histopathological subtypes depending on the predominant pattern. They are known for their aggressive behaviour. As ameloblastomas have a high rate of recurrence, it is necessary to understand the biological behaviour of these neoplasms. Matrix Metalloproteinase-9 (MMP-9) is an enzyme that belongs to Metalloproteinases family and is known to degrade the Extracellular Matrix (ECM) and facilitate tumour progression. Evaluation of the expression of MMP-9 in ameloblastomas could contribute in understanding its biological behaviour. Aim: To analyse the expression of MMP-9 in different histopathological variants of ameloblastoma. Materials and Methods: A cross-sectional observational study was done in the Department of Oral Pathology and Microbiology, Bharati Vidyapeeth Deemed to be University, Dental College and Hospital, Pune, India. A total of 30 cases were selected for this study. The study was carried out for a duration of two years from April 2018 to April 2020. The MMP-9 expression was studied by immunohistochemical staining. The statistical comparison was done using Chi-square test between groups, p-value <0.05 was considered significant. The data was statistically analysed using Statistical Package for Social Sciences (SPSS) version 22.0, IBM Corporation, USA for MS Windows. Results: A total of 30 paraffin embedded archival tissue blocks were selected for this study. Among them nine cases were of Plexiform Ameloblastoma, eight of Unicystic Ameloblastoma, three of Acanthomatous Ameloblastoma, four of Desmoplastic Ameloblastoma and six were of Follicular Ameloblastomas. The MMP-9 showed variable expression in different histopathological subtypes of ameloblastoma. This difference was statistically significant between Plexiform and Acanthomatous as well as Plexiform and Follicular variants (p<0.05). A 66.7% (6 out of 9 samples) of Plexiform Ameloblastoma showed intense staining for MMP-9. Conclusion: Expression of MMP-9 varies in different histopathological variants of ameloblastoma and may not have an association with biological behaviour and aggressiveness.