“I think we’ve come a long way in understanding the importance of this biology. We know it affects men and women, children and adults,” Paul Mischel told the audience during his plenary talk at the 2025 Annual Meeting of the American Association for Cancer Research (AACR 2025). “It’s very prevalent, it’s very devastating. It creates resistance. And we’ve learned some very fundamental rules about this biology that are driving it.”

Cancer therapies can eliminate specific tumors based on their genetic content. However, some cancer cells survive. How do they do it? Part of the answer lies in extrachromosomal DNA (ecDNA), an ace up the tumors’ sleeve to adapt and evade attack. Three simultaneous studies in the journal Nature lay all the cards on the table, revealing ecDNAs’ content, their origin, their inheritance, their influence in cancer, and a way to combat them.

Cancer therapies can eliminate specific tumors based on their genetic content. However, some cancer cells survive. How do they do it? Part of the answer lies in extrachromosomal DNA (ecDNA), an ace up the tumors’ sleeve to adapt and evade attack. Three simultaneous studies in the journal Nature lay all the cards on the table, revealing ecDNAs’ content, their origin, their inheritance, their influence in cancer, and a way to combat them.

Cancer therapies can eliminate specific tumors based on their genetic content. However, some cancer cells survive. How do they do it? Part of the answer lies in extrachromosomal DNA (ecDNA), an ace up the tumors’ sleeve to adapt and evade attack. Three simultaneous studies in the journal Nature lay all the cards on the table, revealing ecDNAs’ content, their origin, their inheritance, their influence in cancer, and a way to combat them.

Cancer treatments for targeting tumor amplifications lag behind those targeting point mutations – and part of the reason may be that amplifications often reside on extrachromosomal DNA (ecDNA). Since ecDNA was first described back in 1965 as minute chromatin bodies in brain cancer cells, the use of large-scale DNA sequencing techniques has revealed the presence of ecDNA across a wide range of cancer types. “The circular structure of ecDNA is associated with increased proto-oncogenic capacity in comparison to linear amplifications. Another key feature is that ecDNA does not contain centromeres,” Roel Verhaak, from Yale School of Medicine, told the audience in a session at the 2023 AACR-NCI-EORTC Conference on Molecular Targets and Cancer Therapeutics in Boston.

A method for parallel sequencing of single-cell extrachromosomal circular DNA (ecDNA) and full-length mRNA transcriptomes has enabled new insights into the roles of ecDNA in cancer progression, researchers from Charité hospital and the Max Delbrück Center for Molecular Medicine reported in Nature Genetics on May 8, 2023. Circular DNAs are present in at least a third of cancer cells, and their presence correlates with poor prognosis in many cases. They can carry driver genes that have separated themselves from their chromosome of origin, and some research suggests that they serve as “reserve copies” of driver genes. Boundless Bio Inc. is in phase I trials targeting ecDNAs.