Other pathways involved in the progression of IPF are represented both by platelet-derived growth factor (PDGF) that contributes to fibroblast activation and connective-tissue growth factor (CTGF) that, through the activation of fibroblasts and the TGF-β pathway, allows for the progression of fibrosis [71]. The gene discussed is TGFB1; the disease is idiopathic pulmonary fibrosis.