FN1 and asthma: We also found that the EMT core regulator such as fibronectin (FN1), SNAI1, and programmed cell death ligand 1 (PD-L1) in the mucosa of asthmatic patients were significantly increased compared with controls (Fig. 2m, Supplementary Fig. 3g-i, and Table S2), suggesting that activation of the EMT process in the airway epithelium of patients with asthma.