TGFB1 and pulmonary fibrosis: In addition to TGFβ, several other fibrogenic factors implicated in pulmonary fibrosis pathobiology, including platelet derived growth factor (PDGF), fibroblast growth factor 2 (FGF2), IL-13, oncostatin M (OSM), and endothelin-1, have been shown to induce IL-11 secretion from fibroblasts and to signal, in part, through the MEK/ERK pathway22,63–66.