As same as the expression of E-cadherin, the expression of occludin, and ZO-1 was respectively decreased in COPD groups (p = 0.001and p = 0.001), and markedly lower in IFCOPD group (p = 0.03 and p = 0.004) (Figure 2). The gene discussed is OCLN; the disease is chronic obstructive pulmonary disease.