Vulnerability to immune therapy in BRAF- and MYB-altered pediatric gliomas.

Authors

null

Michael DeCuypere

Ann and Robert H Lurie Children’s Hospital, Chicago, IL

Michael DeCuypere , Melissa LoPresti , Hinda Najem , Shashwat Tripathi , Joanne Xiu , Hilary Seifert , Valerie I. Brown , Giselle Y. López , Theodore Nicolaides , Craig M. Horbinski , Amy B. Heimberger

Organizations

Ann and Robert H Lurie Children’s Hospital, Chicago, IL, Lurie Children's Hospital, Chicago, IL, NORTHWESTERN UNIVERSITY, Chicago, IL, Northwestern University, Chicago, IL, Caris Life Sciences, Phoenix, AZ, Penn State Milton S. Hershey Medical Center, Hershey, PA, Duke University Department of Anesthesiology, Durham, NC, Caris Life Sciences, Irving, TX, Northwestern Medicine Malnati Brain Tumor Institute of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL, Chicago, IL

Research Funding

No funding received
None.

Background: The frequency and expression of predictive immune biomarkers in pediatric gliomas is relatively unknown. Here, we sought to define predictive signatures of immunotherapy responders by examining immune checkpoint expression, immune cell population signatures, and gene amplifications in a variety of pediatric gliomas. Methods: We profiled a cohort of pediatric, adolescent, and young adult glioma samples submitted to Caris Life Sciences (Phoenix, AZ) for analysis (N = 207). The cohort was further stratified by driver mutations: IDH mutant (N = 103), H3-3A mutant (N = 36), MYB-altered (N = 4), BRAF-altered (N = 39), and IDH wild type [IDH WT] (N = 25). De-identified next generation DNA sequencing (592-gene or whole exome) and RNA (whole transcriptome) sequencing were used to determine tumor-infiltrating immune cell signatures and immune checkpoint protein expression. Transcriptomic signatures predictive of response to immunotherapy (T cell inflamed score) and replication stress response defect (RSRD) score were calculated on transcripts per million (TPM) values. Immune cell fractions were estimated using RNA deconvolution (quanTIseq). Results: BRAF-altered tumors showed the highest IFN gamma signature (a clinically relevant inflammatory biomarker), a high pro-inflammatory M1 macrophage signature, and very high CD4+/CD8+ T cell signatures compared to other tumor groups. IDH mutant, but not WT gliomas, were relatively deficient in T cell infiltration but revealed an increase in dendritic cell signatures. IDH WT gliomas showed more T cell enrichment but higher immune suppressive checkpoint expression. H3-3A mutant tumors showed relatively low immune cell infiltration and immune checkpoint expression. Pro-inflammatory M1 macrophages were lower in the high-grade glioma microenvironment compared to low-grade. Immune suppressive M2 macrophages were elevated in the IDH WT microenvironment relative to other gliomas. There was no apparent difference in the frequency of PD-1+ T cells and tumor-expressed PD-L1 among the various molecularly defined pediatric glioma groups. Conclusions: In general, BRAF- and MYB-altered gliomas displayed high immune activation relative to other tumors. IDH WT tumors have an immune suppressive microenvironment with relatively high immune checkpoint expression. Based on predictive markers, BRAF- and MYB-driven gliomas show signatures suggesting the possibility of a greater response to immunotherapies than IDH WT/mutant gliomas or H3-3A gliomas.

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Abstract Details

Meeting

2023 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Central Nervous System Tumors

Track

Central Nervous System Tumors

Sub Track

Primary CNS Tumors–Glioma

Citation

J Clin Oncol 41, 2023 (suppl 16; abstr 2066)

DOI

10.1200/JCO.2023.41.16_suppl.2066

Abstract #

2066

Poster Bd #

423

Abstract Disclosures

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