P53 EXPRESSION IN BENIGN, PREMALIGNANT AND MALIGNANT LESIONS OF ORAL CAVITY

BACKGROUND Oral carcinogenesis is a multistep process. The premalignant oral lesions, which develop in the epithelial surface due to chronic exposure to various carcinogens such as tobacco, alcohol, betel chewing and HPV infections get transformed to squamous cell carcinoma in genetically predisposed person. Genetic alterations most commonly associated with oral carcinogenesis is p53 tumour suppressor gene mutation. The objectives of this study are, To find out the incidence of various oral squamous epithelial lesions and to evaluate and compare immunohistochemical expression of p53. To assess the degree of p53 staining intensity from dysplasia to malignancy in differentiating benign and malignant lesions. MATERIALS AND METHODS In this prospective study, histopathological examination and immunohistochemical staining was performed to see the p53 expression in these oral epithelial lesions. RESULTS Immunohistochemical expression of p53 observed in 52 cases of oral epithelial lesions consisting of 8 benign, 11 pre-malignant and 33 squamous cell carcinomas. Out of all, 39 cases were showed p53 positivity. The dysplastic lesions account for 11 cases of which p53 positivity seen in 8 (72.72%) cases; p53 immunoexpression was found positive in 26 (78.78%) cases of Squamous Cell Carcinoma (SCC). The staining intensity increased from basal to suprabasal region with increase in grade of dysplasias. CONCLUSION Squamous cell carcinoma was found to be the commonest oral malignant epithelial lesion, in which p53 immunoexpression was found in 78.78% cases. Combined histological analysis with p53 immunoexpression could be a useful and simple molecular marker to detect the possibility of transformation from a premalignant to malignant lesion of oral epithelium.