Caspase cascade pathways in apoptosis of oral lichen planus

ObjectiveApoptosis is frequently found in oral lichen planus (OLP) lesions, but the pathways leading to apoptosis are unknown.Study designThis study focused on analysis of caspase expression which is essential for apoptosis. Expression of caspases 2, 3, 8, 9, and 12 was studied in 70 biopsy samples from atrophic OLP to identify which cascade pathway, extrinsic or intrinsic, is of importance in apoptosis in OLP.ResultsCaspase-2 expression was present in every sample, and >70% of the epithelial cells were positive in 33% of the lesions. More than 70% of the epithelial cells expressed caspase-12 in 84% of the specimens. Caspase-8 expression was shown totally in 87% of the specimens. No caspase-3 expression was found in 57% of the samples, and caspase-9 expression was absent in the entire OLP specimen.ConclusionsThe high frequency of intrinsic apoptotic pathway markers caspases 2 and 12 indicates intracellular stress in atrophic OLP epithelial cells.