HIF1A and idiopathic pulmonary fibrosis: The laboratory of Dr. Delbrel provides evidence that a hypoxic microenvironment and the stabilization of HIF-1α induce ER stress in alveolar epithelial cells; the expression of CHOP, a pro-apoptotic factor currently used as a marker of ER stress in idiopathic pulmonary fibrosis; and subsequent apoptosis [34].