As an extracellular MMPs inducer, CD147 is capable of promoting extracellular matrix remodeling by inducing the secretion of MMPs in fibroblasts and hepatic stellate cells.28,51 Elevated levels of MMPs, including MMP-1, MMP-2, MMP-3, MMP-7, MMP-8 and MMP-9 have been reported in idiopathic pulmonary fibrosis as well as in experimental fibrosis. Here, MMP9 is linked to pulmonary fibrosis.