Background: p53 protein is a product of TP53 tumor Suppressor gene. TP53 mutations leading to loss of function are the commonest type of genetic damage found in human cancers and oral squamous cell carcinomas, often preceding recognizable histological alterations. Ki-67 has been shown to be excellent for the estimation of the growth fraction in both normal and malignant human tissue and this antibody is now used as the usual standard for the assessment of cell proliferation. Aim: To study the expression of p53 and Ki-67 in premalignant and malignant lesions of oral cavity. Material and Methods: The immunohistochemical expression of Ki-67 and p53 was studied on 110 cases of premalignant and malignant lesions of oral cavity during a period from July 2017 to June 2018. Results: The immunohistochemical expression of Ki-67 and p53 showed similar trends, and increased with the degree of dysplasia. On analyzing statistically, a high significant association was found between p53 expression and higher grades of tumour differentiation. However expression of Ki67 did not show significant association with various grades of differentiation of oral squamous cell carcinoma. Conclusion: p53 and Ki-67 are useful biomarkers of malignant transformation in oral precancerous lesion and may serve as intermediate points for cancer prevention programmes.

Keywords: Ki-67; p53; premalignant; malignant; oral lesions