CASP6 and chronic obstructive pulmonary disease: The results of GO analysis (Fig. 4C-D) for 9 COPD-associated pyroptosis-related genes demonstrated that these genes were involed in pyroptosis (CASP4/GZMB/AIM2/CASP6/GSDMC), activation of immune response (IL1B/AIM2/CASP6/PLCG1), regulation of inflammatory response (regulation of inflammatory response) and endopeptidase activity (CASP4/CASP5/GZMB/CASP6).