TB-03IMMUNOPHENOTYPING OF PEDIATRIC BRAIN TUMORS: CORRELATING IMMUNE INFILTRATE WITH HISTOLOGY, MUTATIONAL LOAD, AND SURVIVAL

Abstract

TB-03. IMMUNOPHENOTYPING OF PEDIATRIC BRAIN TUMORS: CORRELATING IMMUNE INFILTRATE WITH HISTOLOGY, MUTATIONAL LOAD, AND SURVIVAL Ashley Plant1,2, Shohei Koyama1, Glenn Dranoff1,3, Mark Kieran1,2, and Jerome Ritz1; Dana Farber Cancer Institute, Boston, MA, USA; Boston Children’s Hospital, Boston, MA, USA; Novartis Institutes for Biomedical Research, Boston, MA, USA The immune landscape of pediatric brain tumors is not well understood. Early literature suggests a correlation between immune infiltrate and histology but its correlation with mutational burden and clinical course has not yet been evaluated. Here, paraffin embedded tissue from 40 pediatric glioblastoma tumors treated atDana FarberCancer Institutewere stained using immunohistochemistry for six immune markers thought to have staging or prognostic significance in other solid tumors including CD45, CD8, CD20, FoxP3, PD1, and PDL1. This data was then compared to mutational burden based on next generation sequencing for known genes involved in cancer pathways and correlation to median survival was evaluated. Subsequently, 40 low grade glioma samples were stained with the same IHC markers as a comparison sample. This data was supplemented with an extensive flow cytometry panel run on the tumor immune infiltrate of fresh tumor samples and also peripheral blood. The immune infiltrate in pediatric brain tumors does not appear to correlate as strongly with histology, grade, and mutational burden as seen in other solid tumors but may correlate with clinical outcome. Neuro-Oncology 18:iii169–iii173, 2016. doi:10.1093/neuonc/now084.3 #The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.