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‹ Wed · 27 May 2026
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Changes in plasma cfDNA ERBB2 copy number reflect prognosis in HER2-positive gastric cancer: a correlative analysis of the KSCC-TROX A2 study

Real-time blood tests tracking HER2 levels during stomach cancer treatment reveal which patients need prompt strategy changes.

In 55 HER2-positive advanced gastric cancer patients enrolled in a phase II trial, longitudinal increase in plasma cfDNA ERBB2 copy number during treatment independently predicted shorter progression-free and overall survival, while baseline ERBB2 CN was not predictive. This real-time liquid biopsy approach offers a practical on-treatment prognostic biomarker for HER2+ gastric cancer management.

What the study was

Study design
Prespecified correlative analysis of phase II trial
Population
HER2-positive advanced or recurrent gastric cancer patients (KSCC-TROX trial)
Sample size
55
Category
Diagnostics
Maturity
Validated
Journal
International Journal of Clinical Oncology

Why it surfaced

Pre-specified correlative analysis of phase II trial adding cfDNA HER2 monitoring for gastric cancer; longitudinal change (ΔCN) independently prognostic in multivariable analysis; ddPCR methodology robust; small n=55 but clean trial-embedded design

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