More abundant NOX4 (Figures 1(g)–1(i)) and TGF-β1 (Figures 1(j)–1(l)) proteins in the epithelial cells and ASM cells were observed in the lungs of COPD patients than the lungs of control individuals by immunohistochemical staining (IHC). Here, TGFB1 is linked to chronic obstructive pulmonary disease.