Some of the gene expression data were quite surprising; for example, MMP-12, which clearly plays an important role in both emphysema and small airway remodeling in the mouse since knockout of MMP-12 is protective against both lesions [18], [19], and which is increased by smoke exposure in 3 month animals, was not increased at all by smoke exposure in 12 month animals (Figure 10). The gene discussed is MMP12; the disease is pulmonary emphysema.