A recent study that identified certain hub genes responsible for increased risk of COPD among smokers has almost cleared the mystery of why only 20–25 percent of smokers eventually develop COPD, though smoking is the main risk factor for the disease. The study by researchers from the First Affiliated Hospital of Guangxi Medical University and Liuzhou People’s Hospital, China, identified 9 hub genes — COL14A1, SULF1, MOXD1, CXCL12, CHRNA1, COMP, POU2AF1, MMP11, THBS2 — associated with COPD. The researchers wrote that both the mRNA and protein expression levels of the hub genes (except that of MMP11) were significantly upregulated in tobacco smoke exposed mouse emphysema models, suggesting the use of these genes as potentially useful biomarkers for identifying smokers with a COPD risk.