Modulation of tumor matrix by components of the plasminogen-plasmin system

This chapter reviews the role of the components of the plasminogen-plasmin system as it pertains to tumor growth, invasion, and metastasis. The identification of an increased expression of urokinase type plasminogen activator (u-PA) in invasive and aggressive malignant tumors offers another important marker for prognostication. Using molecular gene transfer techniques, a tumor cell may be induced to alter its expression of these components of the plasminogen-plasmin system to perturb its growth pattern. The availability of plasmin, generated by u-PA, is an important step in cell migration in both physiologic and pathologic conditions. When homogenates of non-neoplastic human brain and brain tumor tissues have been examined by zymography and by enzyme-linked immunosorbent assay enzyme-linked immunosorbent assays (ELISA), u-PA and plasminogen activator inhibitor (PAI-1) were undetectable in non-neoplastic brain. U-PA and PAI-1 ELISA may offer a potential biomarker and biologic response modifier for the growth of human brain tumors.