Ki-67 Prognostic Value in Different Histological Grades of Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

Abstract

Introduction: Abnormal cell proliferation appears to be a possible predictor of tumorigenesis, Ki-67 protein<br />expression is closely related to the cell proliferation and could be used as a biomarker for the growth in the most of<br />human tumors. The aim of the study: Investigating of Ki-67 expression in the pathological grades of oral epithelial<br />dysplasia and oral squamous cell carcinomas. Materials and Methods: The sample consisted of 30 formalin-fixed,<br />paraffin-embedded specimens of oral epithelial dysplasia (OED), 30 other of oral squamous cell carcinomas (OSCC), and<br />10 normal oral epithelium (NOE) were conventionally stained with hematoxylin and eosin and immunohistochemically<br />stained with Ki-67 monoclonal antibody. Results: Expression of Ki-67 was restricted to the basal layers in the normal<br />oral epithelium whereas Ki-67 positive cells in oral epithelial dysplasia (OED) were located in the basal, suprabasal<br />and spinous layers, Ki-67 expression was increased in high-risk cases. Ki-67 positive cells in well-differentiated<br />(OSCC) were located mainly in the periphery of the tumor nests, in moderately-differentiated (OSCC) were located<br />in both peripheral and part of a center of the tumor nests whereas it was diffused in most of the Poorly-differentiated<br />(OSCC). Statistical analysis indicated a significant difference between the expression in (OED) and (NOE), (OSCC)<br />and (NOE), and no differences between (OED) and (OSCC). Conclusion: This study has concluded that Ki-67 antigen<br />could be used as a marker for the histological grading of OED and OSCC, Expression of Ki 67 increased according to<br />the severity of oral epithelial dysplasia.