title: Monocyte chemoattractant protein-1 expression and macrophage infiltration in gliomas.
abstract: While the number of reports on macrophage infiltration of gliomas is increasing, the extent and mechanisms of macrophage recruitment remain unclear. To investigate whether monocyte chemoattractant protein-1 (MCP-1) plays a role in this process, in situ hybridisation (ISH) was performed for 22 glioblastomas (GBM), 1 anaplastic astrocytoma (AA) and 4 grade II fibrillary astrocytomas (AII) and reverse transcription-polymerase chain reaction was performed in 13 GBM, 1 AA and 3 AII. High levels of MCP-1 mRNA were detectable in most GBM, while a lower level was detected in AII. Many tumour-associated macrophages (TAM) could be demonstrated by immunohistochemistry (IHC) in most GBM, while the AII contained a lower number of TAM. The positive correlation between the MCP-1 level and abundance of TAM suggested that MCP-1 has a role in TAM recruitment. By combining ISH and IHC, high levels of MCP-1 mRNA were shown both in tumour cells and TAM. Along tumour borders, reactive astrocytes and microglia also expressed MCP-1. In areas with T lymphocyte infiltration, larger numbers of MCP-1-positive cells with an enhanced level of expression could be identified. We propose that the mechanism of macrophage recruitment is, at least partly, effected by constitutive expression and T cell-mediated up-regulation of MCP-1 in tumour cells and TAM. The production of MCP-1 by TAM establishes a positive amplification circuit for macrophage recruitment in gliomas.
authors.affiliation: Department of Pathology, University of Hong Kong, Queen Mary Hospital, Hong Kong.
authors.forename: S Y
authors.initials: SY
authors.lastname: Leung
authors.forename: M P
authors.initials: MP
authors.lastname: Wong
authors.forename: L P
authors.initials: LP
authors.lastname: Chung
authors.forename: A S
authors.initials: AS
authors.lastname: Chan
authors.forename: S T
authors.initials: ST
authors.lastname: Yuen
mesh_terms: D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology*; D018932:Chemokine CCL2 / Q000096:biosynthesis*; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008264:Macrophages / Q000502:physiology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000502:physiology
chemical_list: D018932:Chemokine CCL2; D012333:RNA, Messenger