MMP1 and pulmonary emphysema: MMP-1 is involved in airway extra-cellular matrix degradation and alveolar wall stability and is pathogenetically linked to both malignant and nonmalignant chronic respiratory diseases (Elkington et al. 2005; Mercer et al. 2004, 2006; National Heart, Lung, and Blood Institute 2007; Segura-Valdez et al. 2000), including COPD, chronic asthma, emphysema, lung tuberculosis, and bronchial carcinoma.