In influenza-infected mouse lungs, Hif1α promotes ectopic basal cell growth from the airways into the alveolar epithelium.56,57 In mouse fibrotic lungs, Hif2α inhibition attenuates fibrosis and promotes alveolar regeneration.50 These results are consistent with the roles of HIF1α and HIF2α in the developing human lung epithelium. The gene discussed is EPAS1; the disease is influenza.