ctDNA monitoring using tumor-informed copy number analysis.

Journal: EMBO molecular medicine

This study introduces informCNA, a bioinformatics approach to improve detection of circulating tumor DNA (ctDNA) using shallow whole-genome sequencing (sWGS) of cell-free DNA.

Key points:

  • Problem: Conventional ctDNA detection via copy number aberration (CNA) analysis on sWGS typically detects tumor fractions only down to ~3%, limiting utility for early relapse detection and minimal residual disease monitoring.
  • Approach:
    • informCNA uses CNA profiles derived from either tumor tissue or high–tumor-fraction pre-treatment plasma as a personalized reference.
    • It then applies this individualized CNA “fingerprint” to interpret subsequent low-depth plasma sWGS data, increasing sensitivity for low-level ctDNA.
  • Performance:
    • Achieves ctDNA detection at tumor fractions as low as 0.2% across multiple cancer types (based on the data presented).
  • Clinical application in ovarian cancer:
    • Evaluated in 177 serial plasma samples from 18 patients.
    • ctDNA dynamics measured by informCNA were highly concordant with CA-125 trends.
    • informCNA identified recurrence a median of 3.7 months earlier than CA-125.
  • Implications for practice:
    • Demonstrates that personalized CNA-based analysis of sWGS can be a sensitive, minimally invasive, and relatively cost-effective strategy for monitoring disease burden and detecting relapse earlier than standard serum markers in ovarian cancer, with potential applicability across tumor types.

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