title: Bone marrow-derived microglia in pilocytic astrocytoma.
abstract: Tumour associated macrophages (TAMs) are increasingly recognized as supporters of tumour growth. The present study was undertaken to examine benign pilocytic astrocytomas (PAs) for the presence of M2 macrophages. We have asked the question whether TAMs in PAs share the predominant CD163 immunophenotype with tumour-associated microglia/macrophages of malignant gliomas. In addition, we were interested in the question whether there is evidence that the macrophages in PAs derive from resident microglia in surrounding normal brain or whether cells expressing a macrophage phenotype may invade PAs from the vasculature. The latter question is of great interest with regard to so-called "bone marrow-derived microglia" (BMDM) which may provide a physiological route of entry into the CNS that could be used for novel cell-based treatments of brain cancer. In fact, we have found strong morphological evidence for such macrophage recruitment into PAs. We propose therefore that PAs may be used as a model for the study of macrophage recruitment into gliomas. Importantly, our results also confirm that microglia/macrophage infiltration per se is not associated with malignant glioma behaviour.
authors.affiliation: Division of Neuropathology, Department of Pathology and Clinical Laboratory Medicine, Faculty of Medicine, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Wafa
authors.initials: W
authors.lastname: AlShakweer
authors.forename: Yazeed
authors.initials: Y
authors.lastname: Alwelaie
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Mankung
authors.forename: Manuel B
authors.initials: MB
authors.lastname: Graeber
mesh_terms: D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism*; D018952:Antigens, CD34 / Q000276:immunology / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000276:immunology / Q000378:metabolism*; D001254:Astrocytoma / Q000276:immunology* / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism*; D002454:Cell Differentiation / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000276:immunology / Q000378:metabolism*; D046228:Microarray Analysis; D017628:Microglia / Q000276:immunology / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000276:immunology / Q000378:metabolism*; D000098902:CD163 Antigen
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; D011956:Receptors, Cell Surface