NOX4 and pemphigus foliaceus: Studies show that relevant natural products can prevent and treat PF by inhibiting inflammation, ameliorating oxidative stress, and regulating EMT [12], with the mechanisms involving TGF-β1/Smad, p38 MAPK, PI3K/Akt, Nrf2-Nox4, NF-κB, and AMPK signaling pathways.