TY - JOUR
T1 - Translocator protein (TSPO) expression in neoplastic cells and tumor-associated macrophages in meningiomas
AU - Blum, Nadja
AU - Mirian, Christian
AU - Maier, Andrea Daniela
AU - Mathiesen, Tiit Illimar
AU - Vilhardt, Frederik
AU - Haslund-Vinding, Jeppe Lohfert
N1 - © The Author(s) 2023. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc. All rights reserved. For permissions, please email: [email protected].
PY - 2023/11/20
Y1 - 2023/11/20
N2 - Meningiomas are the most common primary intracranial tumors and show extensive infiltration of macrophages. The mitochondrial membrane protein translocator protein (TSPO) has been used as an in vivo marker of microglia and macrophage activation to visualize neuroinflammation. However, it is unknown which cell types express TSPO in meningiomas. Immunohistochemistry of 38 WHO grade 1-3 meningiomas was subjected to segmentation and deep learning classification of TSPO expression to either Iba1-positive tumor-associated macrophages (TAMs) or all other (mainly neoplastic) cells. A possible association between clinical data and TSPO expression intensities was also investigated. TAMs accounted for 15.9%-26% of all cells in the meningioma tissue. Mean fluorescence intensity of TSPO was significantly higher in TAMs (p < 0.0001), but the mass of neoplastic cells in the tumors exceeded that of TAMs. Thus, the summed fluorescence intensity of TSPO in meningioma cells was 64.1% higher than in TAMs (p = 0.0003). We observed no correlation between TSPO expression intensity and WHO grade. These results indicate that both macrophage-lineage and neoplastic cells in meningiomas express TSPO and that the SPECT-TSPO signal in meningiomas mainly reflects the latter; TSPO is expressed equally in parenchymal activated and resting macrophage/microglia lineage cells.
AB - Meningiomas are the most common primary intracranial tumors and show extensive infiltration of macrophages. The mitochondrial membrane protein translocator protein (TSPO) has been used as an in vivo marker of microglia and macrophage activation to visualize neuroinflammation. However, it is unknown which cell types express TSPO in meningiomas. Immunohistochemistry of 38 WHO grade 1-3 meningiomas was subjected to segmentation and deep learning classification of TSPO expression to either Iba1-positive tumor-associated macrophages (TAMs) or all other (mainly neoplastic) cells. A possible association between clinical data and TSPO expression intensities was also investigated. TAMs accounted for 15.9%-26% of all cells in the meningioma tissue. Mean fluorescence intensity of TSPO was significantly higher in TAMs (p < 0.0001), but the mass of neoplastic cells in the tumors exceeded that of TAMs. Thus, the summed fluorescence intensity of TSPO in meningioma cells was 64.1% higher than in TAMs (p = 0.0003). We observed no correlation between TSPO expression intensity and WHO grade. These results indicate that both macrophage-lineage and neoplastic cells in meningiomas express TSPO and that the SPECT-TSPO signal in meningiomas mainly reflects the latter; TSPO is expressed equally in parenchymal activated and resting macrophage/microglia lineage cells.
KW - Brain Neoplasms
KW - Humans
KW - Macrophages
KW - Meningeal Neoplasms
KW - Meningioma
KW - Receptors, GABA
KW - Tumor-Associated Macrophages
UR - http://www.scopus.com/inward/record.url?scp=85177504633&partnerID=8YFLogxK
U2 - 10.1093/jnen/nlad093
DO - 10.1093/jnen/nlad093
M3 - Journal article
C2 - 37952221
SN - 0022-3069
VL - 82
SP - 1020
EP - 1032
JO - Journal of Neuropathology and Experimental Neurology
JF - Journal of Neuropathology and Experimental Neurology
IS - 12
ER -