Based on the above results, the intersections of 1,591 DEGs, 247 COPD-RGs, 2,030 MRGs, and 1,548 PCD-RGs were taken to obtain a total of eight candidate genes (BAG3, BCL2, CCR7, FAM162A, FOXO1, RPS3, SLC39A8, and HINT1) (Figure 1G). This evidence concerns the gene BCL2 and chronic obstructive pulmonary disease.