TGFB1 and lichen planopilaris: Increased gene and protein expression of mesenchymal markers (e.g., vimentin, fibronectin, CDH2) and reduction in the epithelial marker E-cadherin has been shown in lesional LPP HFs, suggesting that the EMT of bulge HF stem cells plays a pivotal role in the fibrotic response seen in this condition [34], likely driven by TGFβ signalling [35,36].