CD44 Expression in Dysplastic and Non-Dysplastic Oral Lichen Planus

Background: Oral lichen planus (OLP) is a relatively common chronic inflammatory autoimmune disease. OLP is more resistant than skin form and malignant transformation into oral squamous cell carcinoma (OSCC) has been reported in this lesion. Since SCC often originates from dysplastic lesions, evaluation of cancer stem cell (CSC) markers in dysplastic and premalignant lesions such as OLP seems to be necessary. Furthermore, chronic inflammation may induce some epithelial malignancies. CD44 as a CSC marker is expressed on epithelial cells and contributes to cell migration and tumor progression. Also, this cell adhesion molecule is expressed on leukocytes involved in various inflammatory diseases. Methods: Thirty samples of erosive/atrophic OLP (15 samples of dysplastic OLP and 15 samples of non-dysplastic OLP), and 10 normal mucosa specimens of the oral cavity were examined using immunohistochemistry. Results: The greatest total score for epithelial immunoreactivity was found in dysplastic OLP, followed by non-dysplastic OLP and normal mucosa with significant differences (P < 0.001). For sub-epithelial lymphocytes immunoreactivity, the greatest total score was reported in dysplastic OLP, followed by non-dysplastic OLP. Conclusions: Significant higher expression of CD44 as a CSC marker in the epithelium of dysplastic OLP may show the role of this marker in malignant transformation and carcinogenesis process of this premalignant lesion. Higher immunoreactivity in sub-epithelial lymphocytes of dysplastic type indicates a probable role of chronic inflammation in the malignant potential of OLP.