Although in the ACO group S100A4 positive basal cells appeared to be higher than the HC (P = 0.3376) and asthma group (P = 0.7417), we noted significantly lower basal cells in ACO than in COPD-ES (P <0.01) and NLFS (P <0.05) groups. This evidence concerns the gene S100A4 and chronic obstructive pulmonary disease.