Detection of KRAS Mutations Using Extracellular Vesicle DNA in Colorectal Cancer Patients

Area of Science:

• Oncology
• Molecular Diagnostics
• Genetics

Background:

• Liquid biopsy using circulating tumor DNA (ctDNA) is valuable for precision medicine in oncology but often lacks sufficient sensitivity.
• Identifying actionable mutations, like KRAS, is crucial for guiding colorectal cancer treatment.
• Novel biomarkers are needed to improve the diagnostic and prognostic capabilities of liquid biopsies.

Purpose of the Study:

• To evaluate the sensitivity of extracellular vesicle DNA (evDNA) as a liquid biopsy target for KRAS mutations in colorectal cancer.
• To compare the diagnostic performance of evDNA and ctDNA for KRAS mutation detection.
• To explore the prognostic value of evDNA concentration in colorectal cancer patients.

Main Methods:

• Observational study of 334 patients with Stage I-IV colorectal cancer.
• Plasma samples collected pre-surgery for evDNA and ctDNA extraction.
• KRAS mutation analysis performed using droplet digital PCR.

Main Results:

• evDNA demonstrated significantly higher sensitivity than ctDNA for detecting KRAS mutations in Stage II and III colorectal cancer.
• evDNA identified KRAS mutations in 13.8% of patients whose tumor tissues were KRAS mutation-negative.
• Higher evDNA concentrations correlated with poorer relapse-free survival in Stage III colorectal cancer patients.

Conclusions:

• Extracellular vesicle DNA (evDNA) offers improved sensitivity for KRAS mutation detection in colorectal cancer liquid biopsies compared to ctDNA.
• evDNA can identify mutations missed by conventional tissue-based testing, potentially expanding treatment options.
• evDNA concentration serves as a potential prognostic biomarker for relapse-free survival in Stage III colorectal cancer.