MMEJ repair of breaks at TA repeats maintains ecDNA and cancer fitness

Nature, Published online: 23 September 2026; doi:10.1038/s41586-026-11048-8Stability of extrachromosomal DNA (ecDNA) relies on microhomology-mediated end joining at fragile TA-rich sites, with FANCM suppressing break formation, suggest…

Nature, Published online: 23 September 2026; doi:10.1038/s41586-026-11048-8

Stability of extrachromosomal DNA (ecDNA) relies on microhomology-mediated end joining at fragile TA-rich sites, with FANCM suppressing break formation, suggesting that Polθ disruption may destabilize ecDNA and sensitize ecDNA-driven tumours to therapeutic intervention.