Correlation between Amelogenin and Osteopontin Expression in Ameloblastomas and Odontogenic Cysts: An Immunohistochemical Study

Background and Aim: Odontogenic tumors are heterogeneous group of lesions originating from odontogenic apparatus and their remnants.Although their etiopathogenesis remains unclear, some advances have been accomplished in understanding the role of their enamel-related proteins.Amelogenin is the major structural enamel matrix protein involved in the development of odontogenic epithelium.Osteopontin is a multifunctional biomarker that affects cell survival, migration, calcification inhibition, and immune cell function modulation.The study aimed to assess the immunoexpression of both biomarkers in different odontogenic lesions.Material and Methods: Forty-eight paraffin-embedded blocks of odontogenic tumors and cysts were involved including multicystic ameloblastoma (n=10), unicystic ameloblastoma (n=9), dentigerous cyst (n=11), odontogenic keratocysts (n=7), and radicular cyst (n=8).Quantitative immunohistochemical analysis for amelogenin and osteopontin were recorded with index of positivity.The results were statistically analyzed using Kruskal-Wallis test and Spearman's coefficient rank correlation analysis. Results:Positive immunoreaction for amelogenin was demonstrated in both control and dentigerous cyst groups while unnoticeable expression was detected in other studied groups.Regarding osteopontin, positivity was detected in ameloblastomas and some examined cysts.Highly statistically significant differences between both biomarkers were revealed in all tested groups (p < 0.001).Spearman's rank analysis reported negative correlation between both biomarkers with highly significant values (p < 0.0001). Conclusion:Amelogenin can be a promising predictor for the biological behavior of odontogenic lesions and pro-invasive factor osteopontin can predict neoplastic potential and high probability of recurrence.