In general, it is plausible to think that the increment of MMP-2, MMP-7, MMP-9, MMP-10, and MMP-12 and the depletion of TIMP-1 observed in our patients with CTD-ILD+ leads to an increase in ECM degradation that affects the adherence of cells to the ECM and triggers the release of cytokines, inflammatory mediators, and growth factors that were trapped in it (such as vascular endothelial growth factor and transforming growth factor-β), providing profibrotic signals from the microenvironment to cells. This evidence concerns the gene MMP9 and interstitial lung disease.