TGFB1 and pulmonary fibrosis: Although the precise origin of myofibroblasts in pulmonary fibrosis is controversial, studies have suggested that they likely derive from TGF-β activated preexisting peribronchial and perivascular adventitial fibroblasts and pericytes, migration of smooth muscle cells from adjacent areas, as well as EMT of type II pneumocytes and endothelial cells [77,78].