Summary: Researchers have found that rogue rings of DNA called extrachromosomal DNA (ecDNA) often appear very early in glioblastoma development and help drive the tumor’s rapid growth, adaptability and resistance to treatment. By integrating patient genomic data, clinical imaging and advanced computational models, the international team showed that many ecDNA circles carry the EGFR oncogene and frequently evolve aggressive EGFR variants.
Because ecDNA can appear before a tumour is fully established, these findings point to a potential window for earlier detection and intervention. The results raise the possibility of blood-based monitoring and new therapies that specifically target ecDNA-driven tumor evolution, which could change how this deadly brain cancer is diagnosed and managed.
Key Facts
- Early appearance: ecDNA carrying cancer-promoting genes, notably EGFR, often arises before glioblastoma forms a full tumour mass.
- Link to aggression: EGFR ecDNA frequently acquires aggressive variants (for example EGFRvIII) that increase tumour fitness and treatment resistance.
- Clinical potential: Detecting ecDNA early — for instance via circulating DNA in blood — could enable earlier diagnosis and personalized treatment strategies based on a tumour’s ecDNA profile.
Source: Queen Mary’s University of London
An international team of scientists has traced how extrachromosomal DNA (ecDNA) — circular DNA elements that exist outside chromosomes — can be an early and dominant force in many glioblastomas, the most common and aggressive primary brain cancer in adults.
The study, led by Dr Benjamin Werner (Queen Mary University of London), Professor Paul Mischel (Stanford University) and Professor Charlie Swanton (The Francis Crick Institute), combines multi-region patient sampling, imaging and rigorous computational simulations to reconstruct the spatiotemporal evolution of ecDNA in treatment-naive glioblastomas.
Published in Cancer Discovery, the research is the first to show that ecDNA carrying oncogenes frequently emerges at the earliest stages of glioblastoma development — in some cases even before a tumour is detectable by conventional means. This early ecDNA accumulation appears to give tumour cells a strong fitness advantage, promoting rapid expansion and increasing the chance that resistant, more aggressive variants will appear.
Tackling glioblastoma’s biggest challenges
Glioblastoma remains one of the most difficult cancers to treat, with median survival around 14 months and little improvement over recent decades. Understanding mechanisms that enable rapid growth and therapy resistance is vital to develop earlier detection strategies and more effective treatments. EcDNA has emerged as an important but complex factor in multiple adult and pediatric cancers, and Cancer Grand Challenges identified deciphering ecDNA biology as a high-priority, high-difficulty objective.
In 2022 the Cancer Grand Challenges-funded consortium eDyNAmiC — an international, cross-disciplinary team of scientists — received support to study ecDNA’s role across cancers. This paper represents a major step forward in that effort, demonstrating how ecDNA shapes tumour evolution in glioblastoma and highlighting new avenues for clinical translation.
Reconstructing a tumour’s evolutionary history
The researchers sampled multiple regions within individual tumours rather than relying on a single biopsy, applying spatially aware genomic analysis and millions of computational simulations. This “archaeological” approach allowed them to infer when ecDNA first appeared, how it spread through the tumour, and how it influenced subsequent clonal expansions.
Across the cohort, the majority of ecDNA rings contained EGFR. EGFR-ecDNA often accumulated prior to clonal tumour expansions and commonly evolved additional changes such as the EGFRvIII variant, which confers heightened aggressiveness and resistance to therapies. The team also observed that ecDNA can carry multiple oncogenes simultaneously, producing complex, gene-specific evolutionary trajectories.
A potential window of opportunity
Because EGFR-ecDNA can arise early and then later give rise to more aggressive variants, there may be a clinically actionable window between ecDNA emergence and the development of resistant subtypes. If reliable assays can be developed to detect early EGFR-ecDNA — for instance using circulating tumour DNA in blood — clinicians might intervene sooner, before tumours become more entrenched and harder to treat.
The study underscores the potential value of tailoring treatments to a tumour’s ecDNA composition. It also highlights open questions: how different therapies influence ecDNA copy number and composition, and whether interventions can prevent the rise of problematic variants. Team eDyNAmiC plans to continue investigating ecDNA across cancer types to identify opportunities for earlier diagnosis, more precise monitoring and smarter therapeutic design.
Charlie Swanton, Deputy Clinical Director and head of the Cancer Evolution and Genome Instability Laboratory at The Francis Crick Institute, emphasizes that these results recast ecDNA as an early and active driver of glioblastoma rather than a passive bystander. By mapping when and how ecDNA arises, researchers hope to open new paths for earlier detection and treatment, potentially improving outcomes for patients with this devastating disease.
Paul Mischel, MD, highlights the translational promise: ecDNA-driven early events may be actionable, suggesting that glioblastoma could be another cancer where ecDNA-informed early detection and intervention might make a clinical difference.
Dr David Scott, Director of Cancer Grand Challenges, notes that the study demonstrates the power of bringing together diverse disciplines and international expertise to address one of cancer research’s toughest problems.
About this glioblastoma brain cancer and genetics research news
Author: Sophia Prout
Source: Queen Mary’s University of London
Contact: Sophia Prout – Queen Mary’s University of London
Image credit: Neuroscience News
Original Research: Closed access. “Extrachromosomal DNA driven oncogene spatial heterogeneity and evolution in glioblastoma” by Benjamin Werner et al., published in Cancer Discovery (DOI: 10.1158/2159-8290.CD-24-1555)
Abstract
Extrachromosomal DNA driven oncogene spatial heterogeneity and evolution in glioblastoma
Oncogenes amplified on extrachromosomal DNA (ecDNA) contribute to treatment resistance and poor survival across multiple cancers, yet the spatiotemporal dynamics of ecDNA remain poorly understood. This study integrates computational modeling with multi-region samples from 94 treatment-naive human glioblastomas to investigate ecDNA evolution over space and time.
The authors report oncogene-specific patterns of ecDNA spatial heterogeneity that arise from random ecDNA segregation and differing fitness effects. Unlike PDGFRA-ecDNAs, EGFR-ecDNAs often accumulate prior to major clonal expansions, confer strong fitness advantages and can reach high abundance. Pretumour ecDNA accumulation was also observed in vivo in genetically engineered mouse neural stem cells. Variant and wild-type EGFR-ecDNAs frequently coexist in glioblastoma; variant EGFR-ecDNAs (most commonly EGFRvIII) derive from preexisting wild-type EGFR-ecDNAs, occur early and reach high abundance. These results indicate that ecDNA oncogenic composition drives distinct evolutionary trajectories, and concepts such as ecDNA clonality and heteroplasmy call for refined evolutionary interpretations of genomic data in many glioblastomas.