S100A4 and pemphigus foliaceus: In this study, we established the BLM-induced PF model in vivo and TGF-β1-induced fibroblasts activation model in vitro, and found that MET was able to alleviate TGF-β1-induced fibroblasts activation and BLM-induced mice PF by down-regulating S100A4 expression through AMPK-STAT3 axis.