HGF and idiopathic pulmonary fibrosis: During a normal wound-healing process, both epithelial and mesenchymal cells release soluble factors that affect the behavior of resident and nearby infiltrating cells5,13, while in vitro studies suggest that in comparison with control normal human lung-derived fibroblasts (NHLFs), IPF lung-derived fibroblasts (IPFFs) make less hepatocyte growth factor (HGF) and prostaglandin E2 (PGE2), both critical factors involved in epithelial repair and suppression of fibrosis11,14 while they exhibit increased IL6 stimulated proliferation and reduced apoptosis15,16.