HIF1A and idiopathic pulmonary fibrosis: As illustrated in Figure 3B, IPF (SN) has increased the level of the pro-apoptotic molecules: pro-caspase 3, cytochrome C, hypoxia-inducible factor 1 alpha (HIF-1a), the high-temperature requirement 2 (HTRA-2/Omi), and the tumor necrosis factor receptor 1 (TNFR1).