Background and purpose: BCL-2 marker has an important role in mechanisms of apoptosis and dysplastic changes, malignancies, and the pathogenicity mechanisms in oral lichen planus (OLP). Current study aimed at investigating the expression levels of BCL-2 in epithelial and connective tissue adjacent in oral lichen planus.
Materials and methods: In this case-control study, investigation of BCL-2 expression was performed in paraffin embedded tissue blocks of 20 cases of OLP (cases) and 20 cases of irritation fibroma (control) obtained from  the Archives of Pathology Department in Dental School, Shahid Sadoughi University of Medical Sciences. Data was analyzed using SPSS V17 applying Chi-Square test and Fisher's exact test. The results were considered significant for a significance level of α=0.05.
Results: There was no statistically significant difference in BCL-2 expression in the basal and parabasal layers of the epithelium between the two groups (P>0.05), but the difference was statistically significant for the connective tissue (P=0.0001).
Conclusion: This study showed that BCL-2 protein may not play an important role in the process of apoptosis in OLP, so, further investigations on other proteins in this process is recommended.