Purpose: To investigate the malignant potential of oral lichen planus (OLP) on the basis of expression of the Fas/FasL markers in healthy individuals (H), OLP patients and patients with squamous cell carcinoma (SCC).
Patients and methods: 40 patients with OLP and two control groups were included in this research (H and patients with SCC). Immunohistochemistry for Fas and FasL was carried out using an avidin-biotin peroxidase complex method.
Results: Only a low percentage of infiltrating lymphocytes and no keratinocytes were Fas-positive in OLP specimens. The highest percentage of Fas-staining keratinocytes in our survey was identified mostly in H and patients with well-differentiated SCC. In most cases of SCC, OLP and H a high percentage of keratinocytes and lymphocytes were FasL-positive. FasL expression was negatively correlated with the degree of cell differentiation and apoptosis. Taking into consideration that all carcinomas in this survey were highly differentiated, it is not surprising that no statistically significant differences in FasL expression between H, OLP and SCC specimens were detected.
Conclusion: Downregulation of Fas expression in keratinocytes and lymphocytes of OLP specimens, together with upregulation of FasL, may serve as initial prognostic biomarker in oral cancer development.