Furthermore, semi-quantitative immunohistochemical analysis revealed an increased S100A4 protein level in intrapulmonary arteries from COPD-patients (mean Δintensity ± sem: 25.29 ± 2.8) in contrast to healthy control lungs (mean Δintensity ± sem: 9.9 ± 5.6; p = 0.032) (Fig. 5c). Here, S100A4 is linked to chronic obstructive pulmonary disease.