GoKawiilStudy finds DNA repair pathway sustains cancer-driving ecDNA circles
Researchers studied how cancer cells repair DNA breaks that occur at TA-repeat sequences within extrachromosomal DNA (ecDNA), circular fragments that often carry amplified oncogenes like MYC. Using cell lines including COLO320DM, HeLa-derived clones and engineered mouse neural stem cells, the team found that a repair mechanism called microhomology-mediated end joining (MMEJ) helps preserve these ecDNA elements and the growth advantage they give cancer cells.