The expression of tumorigenesis markers in oral papilloma

Oral papilloma is the most frequent benign tumor of the oral cavity but its biological potential for malignant transformation is still to be evaluated. The alteration of apoptosis and uncontrolled cell proliferation is considered to be an important factor in oral tumorigenesis. The aim of our study was to evaluate by immunohistochemistry P53, Bcl-2, CD44 and PCNA expression in oral papillomas with and without dysplasia. We examined a series of 55 oral papillomas, including 12(21.8%) cases of papillomas with epithelial dysplasia. Staining patterns were correlated with sex, age, tumor location, size and presence or absence of epithelial dysplasia. P53 showed positive reaction in 70.9%, PCNA in 80%, CD44 in 50.9% and Bcl-2 in 21.8% of papillomas. There was no correlation between sex, age, tumor size, location and presence of dysplastic epithelium in papillomas. We observed a statistically significant correlation between Bcl-2, CD44 expression and presence of epithelial dysplasia in papillomas. Coexistence of PCNA and P53 positive immunostaining was observed. Papillomas with overexpression of P53 and PCNA showed negative reaction for CD44 protein. The results of our study suggest that overexpression of P53 and PCNA might be an early event in oral tumorigenesis, whereas CD44 and Bcl-2 are potential markers of epithelial dysplasia in oral papillomas.