A crucial step in tumor development and metastasis is degradation of the extracellular matrix (ECM). Matrix metalloproteinases (MMPs) are enzymes able to degrade type IV collagen. The proteolytic activity of MMPs is regulated by tissue inhibitors of metalloproteinases (TIMPs). It has been shown that MMP and TIMP expression and concentration correlated with clinicopathological features of tumor, such as tumor stage, depth of tumor invasion, the presence of lymph node and distant metastases. Some clinical investigations have suggested the usefulness of MMP sand TIMPs as prognostic factors for the survival of gastric cancer patients.