NEOLP or EOLP lesions were isolated and cultured for OLP-MFs. 8 Primary OLP-MFs and 6 normal fibroblasts (NFs) were obtained according to methods described by a previous study (12 (link)). Cultured cells at passages 3-6 were used. OLP-MFs and NFs were examined using anti-cytokeratin (1:100; cat. no. AM06387SU-N; OriGene Technologies, Inc.), anti-vimentin (1:200; cat. no. ab92547; Abcam), anti-α-SMA (1:100; cat. no. ab5694; Abcam) and anti-FAP (1:100; cat. no. ab53066; Abcam) antibodies. Growth and viability of OLP-MFs were assessed using a Cell Counting Kit-8 (CCK-8; Dojindo Molecular Technologies, Inc.) at 24, 48 and 72 h, according to the manufacturer's protocol. The cells were rinsed with PBS and fixed overnight in 3% glutaraldehyde at 4˚C. Subsequently, the samples were dehydrated using the following ethanol gradient: 30, 50, 70, 95 and 100%. The samples were then dehydrated with xylene, air-dried at room temperature and embed with epoxy resin. The specimens were coated with gold. The ultrastructure of OLP-MFs and NFs was compared using a transmission electron microscope (magnification, x1.2k) and scanning electron microscopy (magnification, x700), respectively. The images were processed using Adobe Photoshop CS6 (Version 13.0.1; Adobe Systems, Inc.).