Since PFD reduced the severity of silicosis by inhibiting the epithelial mesenchymal transition (EMT), regulating the TGF-β 1/Smad2/3 signaling pathway (Wang et al., 2020; Qin et al., 2021), and inhibiting the production of IL-17A (24), we used it as a positive control in our study. The gene discussed is SMAD2; the disease is silicosis.