In IPF, the regulation of epithelial-mesenchymal transition (EMT) through inhibition of let-7 family members by transforming growth factor β1 (TGF-β1) and a high expression of HMGA2 in alveolar epithelial cells were demonstrated both in vitro and in vivo [111]. Here, TGFB1 is linked to idiopathic pulmonary fibrosis.