TWF1 and idiopathic pulmonary fibrosis: Confocal immunofluorecent microscopy showed that IPF lung myofibroblasts derived from stiff matrix expressed α6-integrin subunit; fluorescent signals from DQ-collagen IV were observed in the periphery of α6-positive lung myofibroblasts, indicative of pericellular proteolysis of collagen IV in the BM (Fig. 2f).