PATH-15. MICROGLIA/MACROPHAGES ARE THE MAJOR TUMOR-ASSOCIATED IMMUNE CELLS IN PILOCYTIC ASTROCYTOMA. (5th November 2018)

• Record Type: Journal Article
• Authors: Chen, Jie; Sinha, Namita; Tihan, Tarik; Ersen, Ayca; J Phillips, Joanna; Gutmann, David; Dahiya, Sonika
• Is Part Of: Neuro-oncology. Volume 20(2018)Supplement 6
• Page Start: vi161
• Page End: vi161
• Publication Date: 2018-11-05
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noy148.671
• Languages: English
• ISSNs: 1522-8517

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.