MMP9 and idiopathic pulmonary fibrosis: In this setting, MMP-7 (Atkinson and Senior 2003; Balci et al. 2023; Inoue et al. 2020; Craig et al. 2015; Pardo and Selman 2006; Richards et al. 2012; Rosas et al. 2008; Song et al. 2013; Todd et al. 2020; Tzouvelekis et al. 2017; Wang et al. 2023a) and MMP-9 (Craig et al. 2015; Pardo and Selman 2006; Todd et al. 2020; Wang et al. 2023a) are the best-reported MMPs and have been postulated as the determining proteins in the development of active fibrosis and the prediction of poor overall survival in IPF.