Introduction: Recent advance in the field of tumour suppressor genes and oncogenes have provided the tool for the study the genetic changes occurring at different stages of carcinogenesis including transition from premalignant to malignant. Methodology: Histopathologically diagnosed benign lesions, premalignant lesions & SCC were included in the study which consist of 33 cases of oral squamous cell carcinaoma (of which14 were well differentiated, 14 moderately differentiated and 02 poorly differentiated) and 03 were verrucous carcinoma. 11 premalignant lesions and 08 were benign lesions of the oral cavity. These cases were subjected to routine H&E staining and p53 immunohistochemical staining. Results: In this study, 4 out of 7(57.14%) cases of hyperplasia showed basal p53 positivity whereas the only cases of squamous papilloma was p53 negative. It was observed that 69% of malignant and 63% of premalignant lesions showed suprabasal p53 positivity whereas only one case of benign lesions showed the above pattern of staining. Conclusion: In conclusion, expression of p53 above the basal layer is an early event in oral carcinogenesis and an indicator of a developing carcinoma preceding morphological alterations.

Keywords: p53 Staining; Benign; Premalignant; Malignant Oral Lesions.