Abstract
Introduction: Focal Adhesion Kinase (FAK) is a membrane-associated molecule, which plays a major role in tumourigenesis by promoting cell survival, proliferation, migration, and invasion. Hence, FAK is a well known molecule that has been targeted therapeutically for the treatment of various malignancies. Ameloblastoma (AB) is a locally invasive, destructive and recurrent benign odontogenic lesion. Based on these properties, we have hypothesized that odontogenic epithelium of AB could show increased expression of FAK.
Aim: To study the expression of FAK in odontogenic epithelium of AB using immunohistochemistry.
Materials and Methods: Thirty four paraffin embedded AB and 17 Dental Follicle (DF) tissues were retrieved from archives. Immunohistochemical staining was performed using FAK antibody on 5 mu m thick formalin fixed paraffin embedded sections. The expression of FAK was studied in ameloblast like cells and stellate reticulum-like cells and was graded as negative, weak and strong. The data was analysed using chisquare test and Fisher's-exact test.
Results: In AB, both ameloblast like and stellate reticulum like cells showed positive expression of FAK in the cytoplasm in all the cases (34). The epithelial islands from all the DFs (17) were negative for FAK expression. The difference in the expression of FAK in ameloblast like and stellate reticulum like cells was statistically significant (p<0.0001). Statistically significant difference was observed in the expression of FAK in stellate reticulum like cells of AB and odontogenic epithelial islands of DF (p = 0.0017). All the AB cases showed strong expression of FAK in ameloblast like cells and negative expression was seen in all the cases of DF.
Conclusion: FAK was strongly expressed in AB as compared to epithelial islands of DF. FAK could be responsible for the neoplastic nature of AB and possibly play a role in tumour invasiveness.