The level of staining for vascular endothelial growth factor (VEGF) in newly generated vessels increased in both smoker groups and the COPD ex-smoker group, which indicated that EMT was an active process in cigarette-associated COPD and reticular basement membrane (Rbm) hypervascularity was related to active EMT in the pulmonary lesions [48]. This evidence concerns the gene VEGFA and chronic obstructive pulmonary disease.