They suggested that MMPs may act synergistically to de­grade the epithelial BM in OLP.[5] Kim et al. reported that under upregulation by bone morphogenetic pro­tein BMP-4, both MMP-1 and MMP-3 expression in OLP may induce epithelial cells acantholysis and lead to erosive changes.[17]. This evidence concerns the gene MMP1 and oral lichen planus.