Patients with CLE have higher white blood cell counts [16] and a unique protease-antiprotease balance, characterized by a higher expression of matrix metalloproteinase 9 (MMP9) and transforming growth factor beta 1(TGFB1).[29] The former has been linked to both emphysema [30,31] and cancer [32,33]. The gene discussed is MMP9; the disease is pulmonary emphysema.