In addition, Cheng et al. (2021) confirmed that metformin reduced cell toxicity, inflammation, EMT, and fibroblast activation in PF by activating the AMPK signaling pathway, while Hua et al. (2021) suggested that icariin may have therapeutic potential for PF by inhibiting myofibroblast differentiation, possibly mediated by PPARγ. The gene discussed is PPARG; the disease is pemphigus foliaceus.