Aim/Background: In the search to refine the prediction of aggressiveness in individual tumours, different biological markers and malignancy grading systems have been used. The aim of the present study was to evaluate the association between histologic grading and expression of p53 at the invasive tumour front (ITF) in oral squamous cell carcinoma (OSCC). Methods: The expression of p53 protein at ITF was assessed by immunohistochemistry. Thirty OSCC patients included 17 men and 13 women with an age range of 30­67 years and a mean age of 51.4 years. Ten normal oral mucosa samples served as control. The data for mean p53 labeling index (LI) was analyzed for difference between low and high grade carcinomas at ITF and centre of the tumour. Results: In low grade carcinomas, the mean p53 LI at ITF was 48.24 (±34.0177); and mean p53 LI at centre was 42.1200 (±31.3014). In high grade carcinomas, the mean p53 LI at ITF was 52.3733 (±38.0615); and mean p53 LI at centre was 45 (±40.2120). The mean p53 LI at ITF was more as compared to mean p53 LI at centre. The mean p53 LI at ITF and centre in high grade carcinomas was more as compared to the mean p53 LI at ITF and centre in low grade carcinomas. The difference was statistically non­significant. Conclusion: There is a high incidence of expression of p53 protein in OSCC. The cells present at ITF have different molecular characteristics when compared with those in the superficial areas of the tumour.

Keywords: Invasive Front Grading; Oral Squamous Cell Carcinoma; p53.