Correlation of histomorphometric parameters and expression of ki 67 to assess the proliferative activity of the epithelium of odontogenic keratocysts

Abstract

Odontogenic Keratocyst (OKC) is an aggressive lesion with wide range of biological and clinical characteristics and a very high recurrence rate (25-60%). This aggressiveness and biological nature of the cyst poses a great challenge to the surgeons in deciding the treatment modality for the management of OKC. The behavior of any pathological lesions can be well understood using immunohistochemical markers, where, Ki-67 is an established proliferation marker that acts as an important diagnostic and prognostic tool. Although immunohistochemistry is a powerful tool in determining the aggressiveness of OKC, yet the histological features could be the indicators for aggressive behavior and thus may help in deciding the treatment of the cyst. Aim: The purpose of the study is to determine the biological behavior of OKCs using histomorphometric parameters and correlating them with the expression of Ki-67 proliferative marker, which might be helpful in formulating the treatment protocol and its regular follow up to decrease the illness in the patients. Materials and Method: The study was conducted on the 38-formalin fixed paraffin-embedded specimen blocks of histopathologically diagnosed cases of OKC. The cases were examined for the histological features on the sections stained with Hematoxylin and Eosin( HandE) like type of keratinization, daughter cyst, odontogenic islands in the connective tissue, corrugations in the lining epithelium, number of infoldings present in the epithelium and the histometrical parameters like height of the epithelium (EH), Total Number of Nuclei (TNN), Number of Basal Nuclei (NBN), Total Nuclear Density (TND), Basal Nuclear Density (BND), Basement Membrane length (BL), and Mitotic Index (MI). The histomorphometric parameters were correlated with the sections stained immunohistochemically with a known proliferative marker, Ki-67. Result: The mean Ki-67 values among the study sample was 15.82+3.06. The mean Ki-67 was correlated with several histometric parameters using Pearson s correlation coeff