CYP1B1 and chronic obstructive pulmonary disease: In this study, the top three differentially expressed genes (DEGs) identified were ME1 (Malic Enzyme 1), NQO1 (NAD(P)H Quinone Dehydrogenase 1), and CYP1B1 (Cytochrome P450 Family 1 Subfamily B Member 1), all of which have well-established roles in COPD pathogenesis.