Matrix metalloproteinase-9 (MMP-9) is an enzyme that plays a crucial role in the breakdown of extracellular matrix proteins. It is involved in processes such as tissue remodeling, wound healing, and cell migration. Dysregulation of MMP-9 has been implicated in various diseases, including cancer, cardiovascular disease, and inflammatory disorders. Research in this area focuses on understanding the mechanisms of MMP-9 regulation and its involvement in disease pathogenesis, with the ultimate goal of developing targeted therapies to modulate its activity.