NQO1 and chronic obstructive pulmonary disease: To assess whether Nqo1-AS1 human homologue expression was associated with smoking amounts and Nqo1 mRNA expression, the expression levels of Nqo1-AS1 human homologue and Nqo1 mRNA in PBMCs of patients with COPD or healthy controls were examined, and the correlation between these two gene expressions and smoking amounts of patients with COPD or healthy controls were analyzed.