apoptosis (1980/15.3%), cancer (1912/14.7%), ROS (1717/13.2%), lung injury (1708/13.2%), infection (1,143/8.8%), pathogenesis (1,131/8.7%), drug (1,068/8.2%), COPD (1,044/8.0%), biomarker (1,038/8.0%), metabolism (1,033/8.0%), TNF-alpha (1,007/7.8%), SOD (999/7.7%), MDA (901/6.9%), mortality (901/6.9%), NRF2 (853/6.6%), MDA (805/6.2%), hypoxia (759/5.8%), LPS (724/5.6%), NF-κB (724/5.6%), cancer cell (699/5.4%), inflammatory cytokine (673/5.2%), glutathione (667/5.1%), macrophage (659/5.1%), caspase (651/5.0%), death (644/5.0%). The gene discussed is TNF; the disease is chronic obstructive pulmonary disease.