Adhesive and invasive features in gliomas

This study aims at the in situ identification of factors mediating glioma c ell invasion requiring adhesion, extracellular matrix degradation, and migr ation. Forty-five gliomas (astrocytomas, glioblastomas, oligodendrogliomas, and mixed gliomas) were investigated for the immunohistochemical expressio n of the membrane protein CD44s, the basal lamina proteins laminin, collage n IV, and fibronectin, the lectin galectin-3 recognizing tenascin and N-CAM , as well as for the matrix-degrading enzymes metalloproteinases MMP-2, MMP -9, and cathepsin D. Besides vessels expressing basal lamina proteins, tena scin, MMP-2, MMP-9, and galectin-3, tumor cells revealed strong immunoreact ivity for CD44s, tenascin, galectin-3, and N-CAM, which was restricted to s olid tumor masses. Single invading cells displayed distinct expression of M MP-2 and MMP-9, also found in solid tumor areas, as well as of cathepsin D. Restricted expression of CD44s, galectin-3, tenascin, and N-CAM in solid t umor masses seems to contribute to homotypical tumor cell adhesion. However , switching to an invasive phenotype, single tumor cells lack this expressi on pattern and acquire degrading and phagocytic activities by expressing ca thepsin D, MMP-2, and MMP-9, which are also expressed by solid tumor masses facilitating the loosening and invasion of single neoplastic cells. The bl ocking of these factors may be of potential benefit in anti-invasive therap y.