COL6A3 and oral lichen planus: We examined across subclusters the expression of pro-inflammatory factors that previously reported to be involved in OLP pathogenesis by subclusters, and found CXCL14, COL6A3, extracellular matrix protein 1 (ECM1), HLA-A genes were highly expressed in clusters 3, which was mainly composed of EOLP (Figure 2D).