This conversation was led by Michalina Janiszewska, Assistant Professor in the Dept. of Molecular Medicine at the Scripps Research Institute. Glioblastoma (GBM), the most aggressive brain tumor, remains an unmet medical need. Despite aggressive chemotherapy, radiation and surgery, only 5.6% of patients survive beyond 5 years post-diagnosis. Targeted approaches have not been successful in this tumor type due to the extreme heterogeneity of GBM. Mosaic amplification of oncogenes suggests that multiple genetically distinct clones are present in each tumor. However, little is known about how different subpopulations of GBM cells interacts with each other or with the surrounding tumor microenvironment (TME). To address this, we employed spatial protein profiling coupled with single-cell spatial maps of fluorescence in situ hybridization (FISH) for key oncogenes frequently amplified in GBM. Our analysis spanned 3-4 areas from 17 formalin-fixed paraffin-embedded (FFPE) GBM cases, 96 sub-regions of interest and total of 35,843 single nuclei. The single-cell FISH signal quantification allowed us to classify tumors based on the relative frequency of co-occurrence of EGFR and CDK4 co-amplification. Interestingly, the tumors with high frequency of cells harboring both amplifications exhibit higher infiltration by CD163+ immunosuppressive macrophages. Thus, our results suggest that high throughput assessment of genomic alterations at the single cell level could provide a measure for predicting the immune state of GBM.
- Walentynowicz et al. preprint, “Single-cell genetic heterogeneity linked to immune infiltration in glioblastoma”