Immunohistochemical analysis of Ki-67 and α-SMA in odontogenic keratocyst, ameloblastoma and pericoronal follicle

Abstract Introduction Ameloblastomas (AM) are considered the most common odontogenic tumors, with great clinical importance linked to its locally aggressive, infiltrative, and recurrent behavior. The odontogenic keratocyst (OK) represents a peculiar cyst that also draws attention because of its aggressive behavior and high rates of local recurrence. Objective The aim of this study was to evaluate the cell proliferation index and the presence of myofibroblasts in AM and OK using Ki-67 and α-SMA antibodies, respectively. Methodology Fifteen cases of AM and 24 cases of OK were selected for immunohistochemical investigation of the proteins α-SMA and Ki-67. A group of 7 pericoronal follicles (PF) was included as control for normal odontogenic tissue. The mean percentage of positive cells was calculated for each protein. Result Kruskal-Wallis test for both markers showed that expression was higher in OK, when compared to AM and PF. Mann-Whitney test showed no statistical difference when comparing the expression of both markers between the subtypes of AM. Conclusion Elevated expression of Ki-67 and α-SMA in OK may be associated with the aggressive clinical behavior of this cyst in comparison to other development cysts. The similar expression of the markers observed among AM and PF cases, as well as among subtypes of AM, may indicate that other factors, besides proliferative potential, are associated with the aggressive behavior of AM.