In all of our papers, we have demonstrated the existence of an overexpression of epithelial proliferation-stimulating proteins (cyclin D1 and substance P/NK-1R) in OLP compared to healthy controls [17,19], which has actually translated into a significant hyperproliferative response in this disease, as assessed by Ki-67 expression [14,17,19]. Here, CCND1 is linked to oral lichen planus.