Abstract

Many authors have described the role ofmatrixmetalloproteinases (MMP) in tumor invasion. MMPs are a family of zinc-dependent endopeptidases, which through degradation of the extracellular matrix (ECM) and the basal membrane induce tumor spread and metastasis. There are more than 20 enzymes classified into 6 groups: Collagenases (MMP-1,-8,-13 and -18), Gelatinases (MMP-2 and MMP-9, Stromelysins (MMP-3,-7,-10,-11,-26,-27), Elastases (MMP-12), Membrane type specific MMPs (MMP-14,-15,-16,-17,-24 H -25) and other MMPs (MMP-19,-20,-28,-21,-22,-23). Many authors have demonstrated a positive correlation between the pattern of MMP expression and the tumor invasive and metastatic potential including: rectal and gastric cancer, lung carcinoma, breast, ovarian, prostate, thyroid cancer and brain tumors. The increased expression of tissue inhibitors of MMPS (TIMPs) is a response against the tumor progression leading to suppression of the MMP-activity and preservation of the ECM integrity. Due to the dual role of TIMPs, which together with MT1-MMP activate pro-MMPs it is possible that the correlation between activator/inhibitor is the one defining the tumor growth and metastasis.