A b s t r a c t : T h e p o t e n t i a l fo r m a l i g n a n t transformation of oral lichen planus is still controversial.The expression of proteins related to cell proliferation and apoptosis in oral lichen planus and epithelial dysplasia was analyzed to evaluate the true potential for malignant transformation of this disease. Twentyfour cases of each lesion were subjected to the streptoavidin-biotin technique for identifying the immunohistochemical expression of PCNA, p53, bax, and bcl-2 proteins. Of the 24 cases of oral lichen planus, 14 (58.33%) were positive for PCNA, 10 (41.67%) for p53, 4 (16.67%) for bcl-2 and 12 (50%) for bax, whereas of the 24 cases of epithelial dysplasia, 20 (83.33%) were positive for PCNA, 10 (41.67%) for p53, 6 (25%) for bcl-2, and 20 (83.33%) for bax. Chi-squared test showed no statistically significant differences between the expression of p53 and bcl-2 in oral lichen planus and epithelial dysplasia, regardless of the grade (P > 0.05). However, the expression of PCNA and bax was significantly increased in epithelial dysplasia (P < 0.05). The results of this study showed that alterations in expression of these proteins are observed in oral lichen planus and epithelial dysplasia, suggesting the potential for malignant transformation in both lesions.
IntroductionOral lichen planus is a chronic inflammatory disease of unknown cause, and its potential for malignant transformation is a subject of much controversy (1). Since the first case was reported in 1910, several studies have suggested that patients with oral lichen planus are at an increased risk of developing cancer (1-7).However, many authors believe that there is insufficient data to prove an association between oral lichen planus and cancer. For these authors, most cases of malignant transformation are the result of errors in the initial diagnosis of the disease (1,8-13).The true potential for malignant transformation of oral lichen planus can be evaluated by analyzing the expression of proteins related to cell proliferation and apoptosis, as alterations in the expression of these proteins are essential for carcinogenesis (14)(15)(16)(17)(18)(19).Therefore, the aim of this study was to evaluate the immunohistochemical expression of PCNA, p53, bax and bcl-2 proteins in oral lichen planus and epithelial dysplasia in order to explain the controversy regarding the potential for malignant transformation of oral lichen planus and emphasize the importance of long-term follow-up of patients with this disease.
Materials and MethodsThe samples used in this study consisted of 24 cases of oral lichen planus and 24 cases of epithelial dysplasia (4 mild, 12 moderate, 8 severe) obtained from the records of