Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that degrade substances withinthe extracellular matrix. The MMP family includes six different groups of enzymes: collagenases, gelatinases, stromelysins, transmembrane MMPs, matrilysins and others. MMPs are secreted as proenzymes that have to be cleaved in order to be activated. Other MMPs, plasmins as well as other factors activate MMPs. MMPs are thought to play an important role in tissue remodeling associated with various physiological and pathological processes. MMP2 degrades type IV collagen and plays an important role in menstrual break down, regulation of vascularization, angiogenesis, and inflammatory response. Mutations of MMP2 are associated with Torg-Winchester syndrome.