TGFB1 and idiopathic pulmonary fibrosis: Elevated expression of TGF-β1 is commonly detected in lung fibrotic lesions, such as IPF and bleomycin-induced lung fibrosis; and overexpression of active TGF-β1 leads to persisting lung fibrosis, whereas inhibition of TGF-β1 signaling by inhibiting or knocking out TGF-β receptors attenuates lung fibrosis in animal models [11–15].