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Updated: May 17, 2025
In Vitro Assay to Study Tumor-macrophage Interaction
Published on: August 1, 2019
Tumour-associated macrophages in human meningiomas
Rahmina Meta1, Henrik Sahlin Pettersen1,2, Sofie Eline Tollefsen1
1Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
Abstract:
Tumour-associated macrophages (TAMs) are regarded as potential therapeutic targets due to "pro-tumoral" and "anti-tumoral" phenotypes. Human meningiomas contain considerable number of TAMs, but their clinical impact is sparsely investigated in these tumours. The aim of this study was therefore to investigate the presence, morphology, and distribution of TAMs in human meningiomas, and relate these findings to histopathology, meningioma subtypes, World Health Organization (WHO) grade, risk of recurrence, and overall survival. In this study, 147 WHO grade 1 and 2 primary meningiomas prepared as tissue micro arrays were included. Standard immunohistochemistry, with the antibodies Iba1 as a pan-marker for "all TAMs", iNOS for M1 and Arginase 1 for M2 TAMs, was performed to investigate their infiltration in the meningioma tissue. The immunostainings were scanned and analysed digitally. TAMs were found in most of the meningiomas with varying amount of ramified and amoeboid appearances. The quantity of total TAMs (Iba1-stained) was found to be significantly higher in the age group ≥ 60 years compared with the younger age group. M2 cell dominated over M1 cell quantity, and a higher quantity of M2 TAMs was found in skull-base compared with non-skull base tumours. Meningothelial subtypes had a higher quantity of M2 TAMs compared with transitional and atypical ones. Furthermore, the M1/M2-ratio was higher in meningiomas linked to the convexities compared with tumours in the basal. No relations between TAMs and histological WHO grade or prognosis (time to recurrence and overall survival) were found. TAMs were common in our series of meningiomas. However, their infiltration showed no clinicopathological significance. Due to their complex dynamic characteristics and shifting phenotypes, the investigation of these immune cells is demanding. Therefore, the TAMs' definite role in human meningiomas in relation to clinicopathological parameters and prognosis need to be further investigated.
Insights
Tumour-associated macrophages (TAMs) are common in meningiomas but do not significantly impact prognosis. Further research is needed to understand their complex role and potential as therapeutic targets in these brain tumours.
Area of Science:
- Immunology
- Oncology
- Neuropathology
Background:
- Tumour-associated macrophages (TAMs) exhibit diverse phenotypes and are potential therapeutic targets.
- TAMs are prevalent in human meningiomas, but their clinical significance remains understudied.
- Understanding TAM infiltration is crucial for meningioma research.
Purpose of the Study:
- To investigate the presence, morphology, and distribution of TAMs in human meningiomas.
- To correlate TAM findings with histopathology, WHO grade, and patient prognosis.
- To explore the clinical impact of TAM phenotypes (M1/M2) in meningiomas.
Main Methods:
- Analysis of 147 primary meningiomas (WHO grade 1 and 2) using tissue microarrays.
- Immunohistochemistry with Iba1 (pan-TAM marker), iNOS (M1), and Arginase 1 (M2) antibodies.
- Digital scanning and analysis of immunostainings to quantify TAMs.
Main Results:
- TAMs were detected in most meningiomas, with varying morphologies.
- Higher total TAM quantity correlated with age ≥ 60 years.
- M2 TAMs predominated over M1 TAMs, particularly in skull-base and meningothelial subtypes.
- No significant association was found between TAMs and WHO grade, recurrence risk, or overall survival.
Conclusions:
- TAMs are common in meningiomas but lack clear clinicopathological significance.
- The M1/M2 ratio varied based on tumour location.
- Further investigation into the dynamic roles and phenotypes of TAMs in meningiomas is warranted.
