Work

Resolving spatial subclonal genomic heterogeneity of loss of heterozygosity and extrachromosomal DNA in gliomas

Year: 2025

Type: article

Abstract: Mapping the spatial organization of DNA-level somatic copy number changes in tumors can provide insight to understanding higher-level molecular and cellular processes that drive pathogenesis. We describe an integrated framework of spatial transcriptomics, tumor/normal DNA sequencing, and bulk RNA sequencing to identify shared and distinct characteristics of an initial cohort of eleven gliomas of varied pathology and a replication cohort of six high-grade glioblastomas. We identify focally amplified extrachromosomal DNA (ecDNA) in four of the eleven initial gliomas, with subclonal tumor heterogeneity in two EGFR-amplified grade IV glioblastomas. In a TP53-mutated glioblastoma, we detect a subclone with EGFR amplification on ecDNA coupled to chromosome 17 loss of heterozygosity. To validate subclonal somatic aneuploidy and copy number alterations associated with ecDNA double minutes, we examine the replication cohort, identifying MDM2/MDM4 ecDNA subclones in two glioblastomas. The spatial heterogeneity of EGFR and p53 inactivation underscores the role of ecDNA in enabling rapid oncogene amplification and enhancing tumor adaptability under selective pressure. Currently, there is limited knowledge about the spatial heterogeneity of glioma-driving molecular events. Here, the authors employ a multiomics approach to characterize the spatial transcriptomic heterogeneity of various types of gliomas and identify spatially distinct tumor subclones with genomic plasticity driven by mutations on extrachromosomal DNA.

Source: Nature Communications

DOI: 10.1038/s41467-025-59805-z