{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Matrix metalloproteinase-9 (MMP-9, 92-kDa type IV collagenase or gelatinase B) is responsible for the degradation of the extracellular matrix (ECM). MMP-9 is produced as a 92 kDa pro-enzyme by neutrophils, macrophages, mast cells and stromal cells, as a normal constituent and released into the extracellular environment after activation in inflammatory tissues. The matrix metalloproteinases (MMPs) and their specific tissue inhibitor metalloproteinases (TIMPs) have been associated with tumor cell invasion and metastasis in a number of adult tumors. MMP-9 may be involved in the development of several human malignancies, as degradation of collagen IV in the basement membrane and ECM facilitates tumor progression, including invasion, metastasis, growth and angiogenesis. The expression levels of MMP-9 in tumors are elevated compared with the corresponding normal tissues in a variety of cancer types."}]}]}