By analyzing large-airway epithelium, alveolar macrophages, and peripheral blood samples from COPD patients by RNA-seq, Morrow et al. [71] observed a significant overlap in genes from large-airway epithelium and macrophage for smoking and airway disease phenotypes, including cytochrome P450 family 1 subfamily B member 1 (CYP1B1) and aryl-hydrocarbon receptor repressor (AHRR). This evidence concerns the gene CYP1B1 and chronic obstructive pulmonary disease.