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Expression of beta2 integrins and macrophage-associated antigens in meningeal tumours
J F Mosnier1, A G Perret, J Y Scoazec
1Service d' Anatomie Pathologique, Hôpital de Bellevue, Saint-Etienne, France. jean.francois.mosnier@wanadoo.fr
Abstract:
This study assessed the expression of leukocyte integrins and macrophage-associated antigens in meningiomas. Fourteen benign meningiomas, ten atypical/anaplastic meningiomas, two hemangiopericytomas and one solitary fibrous tumour (SFT) were included. Frozen sections were immunostained using antibodies directed against leukocyte integrins, CD68, CD14, CD2, CD1a, DRC1 and CD34. Their expression was evaluated semi-quantitatively. Ki67 positive cells were counted. Arachnoid membranes served as controls. Arachnoid cells expressed the beta2-integrin subunit and KP1. Beta2 was detected in the tumour cells of 14 meningiomas. In nine cases, this was associated with an alpha-integrin subunit. There was no statistical difference in the expression of beta2 between benign and atypical/anaplastic meningiomas. KP1 was constantly expressed by the tumour cells of meningiomas. It was not expressed by other meningeal tumours. CD34 was detected in the fibrous meningiomas, hemangiopericytomas and the SFT. In each tumour, macrophages were more numerous than T lymphocytes. There was no statistical difference in the density of macrophages and T lymphocytes between the benign and atypical/anaplastic meningiomas. There was no correlation between the Ki67 proliferation index and macrophage infiltration. Meningiomas, through the expression of leukocyte antigens, have a very particular phenotype. The expression of beta2 integrins could play a role in the attraction of immunocompetent cells in the stroma of meningiomas.
Insights
Meningiomas express leukocyte integrins and macrophage antigens, suggesting a unique cellular phenotype. Beta2 integrin expression may attract immune cells to meningioma tumors.
Area of Science:
- Immunology
- Oncology
- Neuropathology
Background:
- Meningiomas are primary tumors of the meninges.
- Understanding meningioma cell phenotype is crucial for diagnosis and treatment.
- Leukocyte integrins and macrophage markers are key immune cell components.
Purpose of the Study:
- To assess the expression of leukocyte integrins and macrophage-associated antigens in various meningioma subtypes.
- To compare antigen expression between benign and atypical/anaplastic meningiomas.
- To investigate the potential role of beta2 integrins in immune cell infiltration.
Main Methods:
- Immunohistochemical staining of frozen meningioma sections.
- Antibodies against leukocyte integrins (beta2, alpha subunits), CD68, CD14, CD2, CD1a, DRC1, and CD34 were used.
- Semi-quantitative evaluation of antigen expression and Ki67 proliferation index counting.
Main Results:
- Beta2 integrin was expressed in all 14 meningiomas, often with an alpha-integrin subunit.
- KP1 (CD68) was consistently expressed in meningiomas but not other meningeal tumors.
- CD34 was found in fibrous meningiomas, hemangiopericytomas, and SFTs; macrophage density exceeded T lymphocyte density.
- No significant difference in beta2 expression or immune cell density between benign and atypical/anaplastic meningiomas.
Conclusions:
- Meningiomas exhibit a distinct phenotype characterized by leukocyte antigen expression.
- Beta2 integrin expression may facilitate the recruitment of immunocompetent cells into the tumor stroma.
- Further research is needed to elucidate the functional implications of these findings.