TGFB1 and pulmonary fibrosis: One of the key steps in the development of pulmonary fibrosis is the differentiation of fibroblasts into αSMA-expressing myofibroblasts (driven principally by TGFβ) that secrete a number of pro-proliferative factors, and are the major source of collagen and extracellular matrix (Burgess et al., 2005; Scotton and Chambers, 2007) that precipitate remodelling.