Hypothesis

Serial profiling of circulating tumor cells (CTCs) using integrated single‑cell epigenomics, proteomics, and metabolomics will detect epigenetically plastic subpopulations that precede clinical resistance by at least 3 months. Detecting a rise in histone‑acetylation‑linked signaling hubs (e.g., BRD4‑MYC axis) in CTCs before radiographic progression will allow pre‑emptive therapy adjustment, improving progression‑free survival.

Rationale

• Multi‑omics outperforms genomics alone for capturing dynamic resistance layers such as altered protein signaling, metabolic reprogramming, and epigenetic shifts ([1][2][3][4][5]).
• Resistance often arises from rare, epigenetically distinct cancer stem‑like cells that are invisible to bulk DNA sequencing but accessible in CTCs ([5]).
• Histone acetylation changes can rewire transcription factor networks rapidly, creating drug‑tolerant states without new mutations ([3]).
• Plasma‑derived CTCs provide a real‑time window into tumor evolution, enabling longitudinal monitoring that cross‑sectional biopsies miss.

Testable Predictions

1. Baseline stratification – Patients whose CTCs show high baseline H3K27ac enrichment at enhancer regions of EMT‑TF motifs will have shorter time to resistance.
2. Early signal – A ≥1.5‑fold increase in CTC H3K27ac signal at MYC‑associated enhancers, coupled with upregulated acetyl‑proteasome proteins, will predict radiographic progression ≥3 months ahead (hazard ratio >2.0).
3. Intervention impact – Adding a BET inhibitor when the early epigenetic signal appears will delay progression compared with standard of care alone (primary endpoint: PFS improvement).

Experimental Design

• Cohort – 120 patients with EGFR‑mutant NSCLC or HER2+ breast cancer initiating first‑line targeted therapy.
• Sampling – Peripheral blood collected at baseline, every 4 weeks, and at clinical progression.
• CTC isolation – Size‑based filtration followed by immunofluorescence‑based enrichment (EpCAM⁺/CK⁺/CD45⁻).
• Single‑cell multi‑omics – Simultaneous ATAC‑seq (for chromatin openness), H3K27ac CUT&Tag, targeted proteomics (Olink Explore 384), and untargeted metabolomics (LC‑MS).
• Analysis – Build a dynamic regulatory network linking acetylation peaks to protein‑metabolite modules; compute a resistance‑risk score per time point.
• Endpoint – Primary: time from early epigenetic signal increase to radiographic progression. Secondary: PFS after epigenetic‑guided BET‑inhibitor addition vs. control.

Falsifiability

If longitudinal CTC multi‑omics fails to show a consistent, statistically significant lead time (>3 months) between epigenetic‑signaling changes and clinical progression, or if pre‑emptive BET inhibition does not improve PFS, the hypothesis is refuted. Conversely, a positive result would validate epigenetically driven CTC dynamics as a actionable, early‑detection biomarker for resistance, extending current multi‑omics paradigms from static tumor profiling to real‑time, liquid‑biopsy‑guided intervention.