Path-15. Microglia/macrophages Are the Major Tumor-associated Immune Cells in Pilocytic Astrocytoma
Year: 2018
Type: conference-abstract
Abstract: Pilocytic astrocytoma is the most common glioma in children. Although most pilocytic astrocytomas are surgically curable, a small subset does recur and demonstrates CSF dissemination. BRAF-targeted therapies have been applied in recurrent pilocytic astrocytomas. However, a small subset of these tumors lack BRAF alterations. More recently, there has been an emerging role of tumor-associated immune cells (including microglia/macrophages) in gliomagenesis with an attempt to find additional targets as standalone or combined adjuvant therapy. In this study, we investigated composition of different tumor-associated immune cells in pilocytic astrocytomas. Tissue microarrays from 55 pilocytic astrocytomas were generated. Immunohistochemistry for CD3, CD20, CD21, CD68, and CD163 was performed to label different tumor-associated immune cells (T-cells, B-cells, dendritic cells, and microglia/macrophages respectively.) Tumor-associated microglia/macrophages were found at moderate to markedly high density in most pilocytic astrocytomas. CD163 and CD68 positive microglia/macrophages comprised >10% of cells in 67% (37/55), and 60% (33/55) cases. These microglia/macrophages presented as either scattered infiltrate and/or perivascular aggregates. In contrast to microglia/macrophages, lymphocytes and dendritic cells were only found at sparse-to-moderate density. In conclusion, our study reveals that microglia/macrophages are the major tumor-associated immune cells in pilocytic astrocytomas, at least in this small cohort, and raises the possibility of extrapolating tumor-associated microglia/macrophages as a potential therapeutic target in pilocytic astrocytomas.
Source: Neuro-Oncology
Language: English
Subfield: Genetics
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2899780593