TGFB1 and chronic obstructive pulmonary disease: We examined the association between LVRS outcomes and variants in five genes previously shown to be associated with chronic obstructive pulmonary disease (COPD) susceptibility, exercise capacity, or emphysema distribution on chest CT [3-7]: glutathione S-transferase pi (GSTP1), microsomal epoxide hydrolase (EPHX1), transforming growth factor beta-1 (TGFB1), serpin peptidase inhibitor E2 (SERPINE2) and surfactant, pulmonary-associated protein B (SFTPB).