Immunohistochemical Analysis of PCNA and P53 Proteins in Oral Lichen Planus, Oral Dysplasia and Normal Oral Mucosa

Abstract

Background: The overexpression of the protein products of genes associated with the cell cycle protein p53 and PCNA is apparently of great significance. Oral lichen planus classified among the potentially malignant lesions of oral mucosa. The aim of this study is to evaluate and compare the tissue expression PCNA and p53 proteins in oral lichen planus, epithelial dysplasia cases and normal oral mucosa. Materials and methods: Formalin-fixed and paraffin- embedded blocks of 21 lichen planus, 21 oral dysplasia and 10 of normal oral mucosa cases were used in immunohistochemical (IHC) analysis for PCNA and p53 monoclonal antibodies. Results: The mean of PCNA expression in OLP (44.14) was less than in the control group (74) and there was an opposite result of p53 (12.19) when compared with the control group (1.05), and in cases of epithelial dysplasia the same result was found and the mean PCNA value in epithelial dysplasia was significantly higher than those found in controls and in oral lichen planus. There was a statistically significant difference between the expression of p53 and PCNA proteins in oral lichen planus cases and non- significant differences of both proteins expression in oral dysplasia cases. Moreover, there was a significant positive correlation between the numbers PCNA and p53 percentage of positive cells in oral lichen planus group. Conclusion: The proportion of cases with positive PCNA and p53 expressions increased from normal oral mucosa to lichen planus to epithelial dysplasia. These results may indicate the presence of high degree of PCNA and p53 proteins in chronic and premalignant lesion like oral lichen planus and epithelial dysplasia can be great helpful in their prognosis and suggested treatment.