Nucleosome Profiling of cfDNA Distinguishes Recurrent Breast Cancer with AUC 0.826 in 150-Sample Retrospective Study

The team examined cfDNA fragment length and nucleosome occupancy at hormone-therapy resistance loci rather than sequence variants alone. In 105 primary and 45 recurrent or metastatic cases, recurrent disease showed shorter fragments and altered nucleosome positioning at RERE and SYNPO2. A composite score from these two regions plus machine-learning integration of additional cfDNA features yielded the reported AUC. Absolute performance metrics were not stratified by subtype or prior therapy, limiting immediate translation.

Existing ctDNA mutation panels detect recurrence with 60-75% sensitivity in hormone-receptor-positive disease but miss non-mutated regulatory shifts. The nucleosome approach captures chromatin-state changes linked to endocrine resistance, a gap highlighted in prior observational cohorts such as the 2022 NEJM ctDNA study in high-risk patients. However, the current design cannot separate subtype-specific signals from treatment effects or batch variation in fragmentomics.

Larger prospective studies must enroll balanced subtype cohorts, pre-specify thresholds, and compare against imaging and CA15-3. Regulatory clearance will require demonstration that earlier detection alters progression-free survival, not merely AUC. Funding disclosures and independent replication remain essential before any surveillance claim.

Next steps include a multi-center validation trial targeting 500 patients with serial sampling through 2028 to test whether the assay detects recurrence at least six months before standard imaging with sensitivity above 80%.