TGFB1 and idiopathic pulmonary fibrosis: Xie et al. found that PTEN expression is significantly reduced in Chinese patients with IPF; furthermore, a mechanistic study using TGF-β1-induced human embryonic lung fibroblasts (HFL-1) indicates that loss of PTEN resulted in activation of PI3K/Akt and TFG-β/Smad3 pathways [102].