Whilst FIH is stably constitutively expressed across tissues (Bracken et al., 2006; Stolze et al., 2004), the activity levels of FIH can vary (Wang et al., 2018; Tan et al., 2007; Kroeze et al., 2010); thus, we compared FIH activity in control or IPF fibroblasts using a UAS-luc/GAL4DBD-HIF1αCAD binary reporter system (HIF1α CAD reporter) (Coleman et al., 2007). This evidence concerns the gene CASR and idiopathic pulmonary fibrosis.