CCN2 and idiopathic pulmonary fibrosis: Transforming growth factor beta (TGF-beta), connective tissue growth factor (CTGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and Th2 immune response cytokines, mainly IL-4, IL-13, are the main regulatory factors involved in this process in patients with IPF [12,55,56].