As shown in Figure 9(d), compared with the control group rats, the phosphorylation levels of EGFR, MEK, and ERK1/2 and the protein expression levels of SPDEF in the lungs of COPD rats were all increased, and the overexpression of these proteins was significantly reduced by ECC-BYF III and NAC (P < 0.01). This evidence concerns the gene EGFR and chronic obstructive pulmonary disease.