Alterations of whole genome and extrachromosomal circular cell-free DNA fragmentomes across the cancer care continuum

The origins and properties of cancer-associated genetic changes in cell-free DNA (cfDNA) are not fully understood. Through genome-wide analyses of 1,807 samples from 1,064 patients across eight common cancer types, we identified extrachromosomal circular DNA (eccDNA) as a source of cfDNA fragments. Characterization of eccDNA-derived cfDNA fragments along with single base substitutions, small insertions and deletions, rearrangements, and phased variants in single cfDNA molecules, revealed differences between tumor tissues and cfDNA, with an increase in tumor-derived cfDNA alterations at epigenetically repressed regions and a decrease at active promoters. Combination of variant characteristics with individual error rates and machine learning analyses enabled tumor-informed and tumor-independent measures of circulating tumor DNA for early detection, detection of minimal residual disease, and for monitoring patients during therapy. The universal nature of eccDNA and other tumor-derived characteristics of cfDNA may be broadly useful for cancer detection.

• Type: Whole Genome Sequencing
• Archive: European Genome-phenome Archive (EGA)