GDF-15 is an epithelial stress marker that is elevated in patients with idiopathic pulmonary fibrosis (IPF), a predictor of more severe disease and worse outcomes in IPF and associated with a greater odd of developing interstitial lung abnormalities (ILA) in both the FHS and COPDGene cohorts [38, 39]. This evidence concerns the gene GDF15 and pulmonary fibrosis.