VDR and oral lichen planus: MicroRNA-26a / b significantly decreased in serum, saliva and OLP tissue samples. They showed that there are sites for VDR binding in the promoter region of the MicroRNA-26a / b gene and that Vitamin D / VDR signaling induces MicroRNA-26a /b in OLP. MicroRNA-26a / b has a protective role in OLP through inhibition of apoptosis and reduction of pro-inflammatory cytokines in epithelial cells.