The expression of IGF-1 mRNA is downregulated in lung tissues from patients with idiopathic pulmonary fibrosis (IPF) or sarcoidosis, while basal or TGF-β1-stimulated IGF-1 expression is higher in fibroblasts collected from IPF or fibrotic (Phase III or IV) sarcoidosis than health controls [93, 94]. Here, IGF1 is linked to sarcoidosis.