Sasmita Sahu, Pramita Sahu

BACKGROUND Oral squamous cell carcinoma (OSCC) has become one of the leading causes of death mostly in developing countries with worldwide estimated incidence of around 3,00,000 and accounts for more than 95% of oral cancers. Oral epithelial dysplasia (OED) is a modified epithelial tissue that shows cytological changes, specifically severe dysplasia, related to increased risk of developing OSCC. The present study is undertaken to evaluate the role played by p16 and p53 on oral carcinogenesis, their use as biomarkers of malignant transformation of OED and as predictor of biological behaviour of OSCC. We wanted to determine the immune expression of p16 and p53 in the tissue obtained from squamous dysplasia and squamous cell carcinoma lesion of oral mucosa and establish the possible relation of p16 and p53 expression to histologic grading of OED and OSCC. METHODS Materials consisted of 14 histologically diagnosed cases of hyperplasia without dysplasia oral mucosa, 20 cases of dysplastic lesions (3 mild, 5 moderate and 12 severe dysplasia) and 40 cases of SCC lesions (28 well differentiated, 9 moderately differentiated and 3 poorly differentiated) of oral mucosa. These cases are subjected to routine H & E staining and p53, p16 immunochemical staining. RESULTS p16 positivity found in 50% of hyperplastic, 35% of dysplastic and 10% of carcinoma lesions of oral mucosa and this association was to be significant (p value= 0.004). Intensity of p16 gradually decreased with increase in severity of lesion with 42% of benign, 29% of premalignant and 25% of malignant cases showed strong intensity. p53 positivity was seen in 21% of hyperplastic, 60% of dysplastic and 75% of carcinoma lesions showing a significant association (p value= 0.001). p53 staining confined to basal layer was observed in 66% of hyperplastic and 17% of dysplastic lesions but none of carcinoma lesions showed this pattern. CONCLUSIONS p16 and p53 could not be specific enough to identify patients suffering from OED with high risk of malignancy. However, the evaluation of their presence can be used as an effective tool to evaluate the progression of dysplastic changes in the development of OSCC in conjunction with histological parameters.