S100A4 and chronic obstructive pulmonary disease: S100A4 mRNA expression was higher in arteries from the lungs of COPD patients (mean ΔCt ± sem: 4.44 ± 0.56) as compared to healthy donors lungs (mean ΔCt ± sem: 1.54 ± 1.1; p = 0.047) (Fig. 4d).