International Journal of Oral and Maxillofacial Pathology2231 - 22502120110324p53 expression in oral submucous fibrosis & oral cancer914ENNishatShamSultanaRajiv Gandhi University of Health Sciences, Vydehi Institute of Medical and Dental Sciences, Bangalore.. email@example.comShambulingappaPallagattiAliImamMohamed22.214.171.12401101162011032420110210Background and objectives: Expression of p53 tumor suppressor gene is one of the common findings in human cancers including the oral cancer. The product of p53 gene, p53 protein is known to be expressed in premalignancies and Squamous cell carcinoma, but only few literatures is available regarding p53 expression in oral sub mucous fibrosis ,Hence this study was carried out to (i) determine the expression of aberrant p53 in OSMF and OSCC (ii) to study to study correlation if any between p53 expression and degree of dysplasia in OSMF and OSCC patients and (iii) to study correlation if any between p53 expression and habits in OSMF and OSCC patients. Methods: 30 biopsy specimens from OSMF cases and 30 specimens from OSCC cases were subjected for staining by immunohistochemistry for p53 protein using monoclonal primary antibody DO-7 by LSAB visualization system kit. Clinical details along with habits were recorded and the data analyzed with chi-square test and fisher exact test. Results: The results of study revealed 15 cases of OSMF and 24 cases of 0SCC being positive for p53 protein. Among which only 3 cases of OSCC showed (+ +) moderate degree of dysplasia and the rest all had (+) mild dysplasia and in OSMF all 15 cases showed (+) mild degree of dysplasia. 19 out of 22 patients of OSCC and 15 of 25 OSMF patients with chewing habit showed positivity for p53 staining. Interpretation and conclusion: This study demonstrates a high incidence of p53 over expression in OSMF and OSCC. The results indicate that p53 over expression may play a role in the development of Oral squamous cell carcinoma and in pathogenesis of OSMF. Arecanut chewing and/or smoking in OSMF and OSCC cases may play a role in the p53 over expression.