Laminin expression by glial fibrillary acidic protein positive cells in human gliomas

Extracellular matrix components are regarded as important substrates for in vasive tumor cells. The present work focuses on the expression of laminin i n the brain in response to invading brain tumors. Biopsies obtained from ti ssue macroscopically evaluated as the border zone between tumor and normal brain, in 5 patients undergoing surgery for glioblastoma multiforme, were e xamined by immunocytochemistry and scanning confocal microscopy for the exp ression of laminin and glial fibrillary acidic protein. Laminin was mainly found in all the specimens associated with the basal lamina of blood vessel s, but a variable degree of punctate laminin deposits were also observed in the parenchyma not associated with blood vessels. In the specimens with su bstantial deposits, scanning confocal microscopy showed that some of the la minin co-localized with intracellular glial fibrillary acidic protein. Punc tate deposits of laminin were also seen in an intracranial BT4C rat glioma model, where it was particularly abundant in the brain/tumor confrontation zone. Previous in vitro studies have shown that laminin, among several extr acellular matrix components, represent a highly permissive substrate for gl ioma cell migration. The presented results indicate that laminin can be pro duced by glial fibrillary acidic protein positive cells during glioma cell invasion in humans. This glycoprotein may thus represent one important subs trate among many, which contribute to the invasive phenotype of gliomas. (C ) 1999 ISDN. Published by Elsevier Science Ltd. All rights reserved.