Tenascin expression patterns and cells of monocyte lineage: Relationship in human gliomas

Stromal extracellular matrix (ECM) components are thought to play an import ant role in regulating invasion of human gliomas. Macrophages and microglia l cells may heavily influence the integrity of the extracellular compartmen t of gliomas, and the affected ECM may play a key role in regulating migrat ory activity of both tumor cells and macrophages/ microglia. The aim of thi s investigation was to study immunohistochemically the expression patterns of four ECM components: fibronectin, laminin, collagen IV, and tenascin (TN ) in human gliomas, with special attention to TN. Our main goal was to stud y the possible correlation between TN expression and macrophagic/microglial infiltration in gliomas. Altogether, 90 gliomas were studied. Tumors inclu ded 46 glioblastomas, 19 anaplastic gliomas, 22 low grade gliomas, and 3 pi locytic astrocytomas. Vascular TN prevailed in perinecrotic areas of gliobl astomas, whereas interstitial TN was more often expressed distant from necr osis and in the ECM of anaplastic and low grade gliomas. Double staining wi th CD68 and anti-TN antibodies showed that macrophagic/microglial density w as significantly higher in TN-positive areas of most of the glioblastomas a nd anaplastic gliomas, whereas microglial percentage from total number of C D68-positive cells was in most of the cases significantly higher in TN-nega tive areas. In addition, we saw a morphologically spatial correlation betwe en higher densities of macrophagic/microglial infiltration and TN expressio n in perinecrotic areas in glioblastomas. Attachment of macrophages to TN-p ositive basement membrane zones of newly formed stromal blood vessels was e vident. On the basis of our results, we conclude that TN may play a crucial role in regulating trafficking of cells of monocyte lineage in human gliom as.