Plasma cell-free DNA chromosomal instability analysis by low-pass whole-genome sequencing to monitor breast cancer relapse.

cfDNA CIN yields a higher accuracy in monitoring breast cancer recurrence compared to traditional biomarkers (CA15-3 and CEA), especially for biomarker-negative patients. The combination of cfDNA CIN to traditional biomarkers further improved the detection rate of recurrence, which may provide a new method for monitoring the early relapse of breast cancer, though further investigations are warranted.