Immunohistochemical localization of extracellular matrix proteins in human glioma, both in vivo and in vitro

Expression of type IV collagen, fibronectin and laminin in various types of primary human brain tumor sections and normal brain tissue sections as well as in cultured glioma cell lines was examined by an immunofluorescence technique. Type IV collagen, fibronectin, and laminin were mainly localized to the basement membrane of the vasculature in glioblastoma, anaplastic astrocytoma, low grade glioma, and in normal brain. However, positive staining for all the extracellular matrix (ECM) components tested was found only in glioblastoma sections both in the cells and in the ECM. In all other tumor types and in normal brain tissue, the cells did not stain for any of the ECM components. Four glioblastoma cell lines and autologous ECM synthesized by respective glioblastoma cell lines also showed positive staining for type IV collagen, fibronectin and laminin in vitro. These results suggest that glioblastoma cells both in vitro and in vivo express the extracellular matrix components that are involved in the regulation of tumor cell invasion.