Having observed increased TGFβ1 levels at baseline in IPF and SSc fibroblasts and induction of TGFβ2 and TGFβ3 levels by IGF-II, we examined the impact of inhibiting the shared TGFβ receptor on the IGF-II fibrotic response. This evidence concerns the gene TGFB3 and idiopathic pulmonary fibrosis.