Recently, a study showed that the expression of MMP-9 along with NF-κB was increased in CS extract stimulated peripheral blood mononuclear cells (PBMCs) and murine alveolar macrophage cells and in a CS-induced emphysema rat model (Hou et al., 2015; Li et al., 2015). The gene discussed is NFKB1; the disease is pulmonary emphysema.