Development of a cfDNA 5mC/5hmC-based Biomarker Panel to Predict Targeted Therapy Efficacy in mCRC

Metastatic colorectal cancer (mCRC) remains one of the leading causes of cancer-related death. Although targeted agents such as anti-EGFR (cetuximab, panitumumab) and anti-VEGF (bevacizumab) therapies have improved survival, treatment response varies widely even among molecularly defined subgroups.

Traditional biomarkers, including RAS/BRAF mutation and tumor sidedness, fail to accurately predict therapeutic efficacy.

Recent studies highlight the potential of cell-free DNA (cfDNA) methylation (5mC) and hydroxymethylation (5hmC) as sensitive, non-invasive indicators of tumor biology and treatment dynamics.

The EpiDRIVE study integrates cfDNA 5mC/5hmC sequencing and targeted validation to discover and verify epigenetic determinants of therapeutic response.

Discovery phase: Whole-genome 5mC/5hmC profiling to identify differentially modified regions between responders and non-responders.

Training phase: Targeted sequencing to establish a predictive cfDNA epigenetic panel (EpiDRIVE panel).

Validation phase: qPCR-based validation of selected markers in an independent cohort to confirm predictive accuracy.

This study aims to provide a non-invasive biomarker framework to predict and monitor efficacy of EGFR- and VEGF-targeted therapies in mCRC, ultimately guiding personalized treatment selection.

Inclusion criteria

• Histologically confirmed metastatic colorectal adenocarcinoma (mCRC).
• Received EGFR-targeted therapy (cetuximab/panitumumab) or VEGF-targeted therapy (bevacizumab).
• Availability of pre-treatment plasma sample for cfDNA analysis.
• Documented radiologic response evaluation (RECIST 1.1).
• RAS/BRAF mutation status known.

Exclusion criteria

• Inadequate cfDNA quality or low cfDNA yield.
• Non-adenocarcinoma histology.
• Concurrent or prior other active malignancy.
• Active inflammatory or autoimmune disease affecting cfDNA methylation profiles.