Expression of Urokinase-Type Plasminogen Activator Receptor (uPAR) in Primary Central Nervous System Neoplasms

Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry (Impact Factor: 2.01). 07/2005; 13(2):184-9. DOI: 10.1097/01.pai.0000138448.85231.da
Source: PubMed


The cellular receptor for urokinase-type plasminogen activator receptor (uPAR) is a member of the glycosylphosphatidylinositol (GPI) anchored protein family. It is a specific cell surface receptor for its ligand, urokinase-type plasminogen activator, which catalyzes the formation of plasmin from plasminogen to generate the proteolytic cascade and leads to the breakdown of the extracellular matrix. uPAR has been shown to correlate with a propensity to tumor invasion and metastasis in several types of non-central nervous system tumors. In this study, the authors examined the immunohistochemical expression of uPAR in 65 primary brain tumors (5 pilocytic astrocytomas, 5 diffuse astrocytomas, 6 anaplastic astrocytomas, 8 glioblastomas, 5 oligodendrogliomas, 4 oligoastrocytomas, 6 anaplastic oligoastrocytomas, 4 gangliogliomas, 4 ependymomas, 5 medulloblastomas, 6 schwannomas, 5 meningiomas, 2 atypical meningiomas). The specimens were evaluated for intensity of immunostaining (0-3 scale), cellular localization of staining, and specific or unique patterns of staining. Some degree of uPAR expression was observed in all tumors. A significant positive correlation (P = 0.0006) between tumor grade and staining intensity was identified within the astrocytoma/glioblastoma subgroup, suggesting a possible correlation with anaplastic change and propensity to tumor invasion. Expression of uPAR in nonmalignant, noninvasive tumors such as schwannoma and meningioma suggests that uPAR may have other biologic functions in addition to promotion of tumor invasion.

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    • "The urokinase-type plasminogen activator receptor (uPAR) is overexpressed in many human cancers, its expression often correlating with poor prognosis (Memarzadeh et al., 2002; Kaneko et al., 2003; El-Kott et al., 2004; Salajegheh et al., 2005; Meng et al., 2006; for review see Bene et al., 2004). It is expressed as a glycosylphosphatidylinositol (GPI)-anchored plasma membrane protein and in a soluble form that is secreted or shed from the cell surface (Pedersen et al., 1993; Pyke et al., 1993; Blasi and Carmeliet, 2002). "
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