Evaluation of epithelial cell proliferation in Ameloblastoma and Keratocystic Odontogenic tumor: A comparative study

Background: Ameloblastoma (AM) and keratocystic odontogenic tumor (KCOT) are the most common odontogenic tumors which exhibit aggressive clinical behavior. The aggressive behavior of the AM and KCOT can be correlated with the degree of proliferation of the epithelium. Objective: The objective of the study was to determine the proliferation potential of AM and KCOT to correlate with the aggressive clinical behavior. Materials and Methods: The study material consisted of 10 solid AMs, 10 KCOTs, and 5 oral squamous cell carcinomas (SCCs). Sections were immunohistochemically stained with the Ki-67 antibody. Representative fields were randomly selected in each immunohistochemically stained section. Counting was done under Olympus compound microscope fitted with an eyepiece ×10 magnification and objective ×40 magnification. Ten fields were chosen for each section. In AM, peripheral tall columnar cells of tumor islands/nests/cords were selected. In KCOT fields were selected in the basal and the suprabasal region of the epithelial lining. Differences in the average number of Ki-67-positive cells per field among all the three groups (AM, KCOT, and SCC) were analyzed by using the Kruskal–Wallis test. Results: AM showed expression of Ki-67 in peripheral tall columnar cells and the count was 10.83 ± 1.76, whereas in KCOT Ki-67-positive cells were present in the basal and suprabasal layer with a positive cell count of 9.4 ± 0.45. There was no statistical difference between AM and KCOT ( P > 0.005). The value obtained indicates the equal aggressive nature of the above lesion in consideration. Conclusion: The proliferative potential of the epithelium in odontogenic tumors is quite significant for their clinical behavior. Similar expression count of Ki-67 in AM and KCOT explains their aggressive clinical behavior and a high recurrence rate.