Lung sections were labeled for i) ACO1, Ki67, and E-cad (Supplementary Figure SE3A-F) or ii) vWF, Ki67, and E-cad (Figure E3G and E3H) to determine if an abundance of ACO1-positive VECs in IPF is attributed, at least in part, to their active proliferation. The gene discussed is MKI67; the disease is idiopathic pulmonary fibrosis.