We successfully identified an ECM protein signature shared between IPF and SSc that differentiates disease from healthy fibroblasts, which included several proteins implicated in fibrogenesis such as PLOD2, LUM, POSTN, IGFBP5, GREM1, and SPARC, as well as less characterized ECM proteins such as MXRA5, LEPRE1, MFAP4, and FSTL1. This evidence concerns the gene FSTL1 and idiopathic pulmonary fibrosis.