Pulmonary tissue oxygen levels are hard to quantify but a role for hypoxia in the progression of pulmonary fibrosis has been supported by the observation that there is increased stabilisation of the hypoxia-inducible transcription factor (HIF-1α) in lung tissue taken from patients with IPF as well as in mice with bleomycin-induced pulmonary fibrosis[6]. This evidence concerns the gene HIF1A and pulmonary fibrosis.