PTGS2 and chronic obstructive pulmonary disease: The top 22 targets with “degree > 122, closeness > 150” in the PPI network were selected (Figure 6(a)), which were AKT1, IL-6, JUN, VEGFA, CASP3, IL-1B, ESR1, PTGS2, EGFR, MYC, HIF1A, MAPK3, STAT3, etc. These targets were suggested to be the core genes of YQJPR in treating COPD, and then, a subnetwork (Figure 6(b)) was constructed for the core genes.