Detection and Monitoring of BRAF and KRAS Mutations in Cell-Free Urinary DNA of Metastatic Cancer Patients by Droplet Digital PCR
- BRAF and KRAS mutations confer a survival and growth advantage to cancer cells and can be used for selection of targeted therapies.
- Cell-free (cf) DNA detected in the urine of individuals with cancer offers an easily obtainable, low-risk, and inexpensive source of biologic material for mutation analysis.
- Longitudinal assessment of BRAF and KRAS mutations in urinary cfDNA can be used for monitoring of molecular changes throughout cancer therapy.
- A total of 27 patients with advanced cancers and 5 patients with Erdheim-Chester disease (histiocytic disorder with high prevalence for BRAF mutations), who were previously tested for mutations in BRAF and/or KRAS a CLIA-certified laboratory were prospectively enrolled.
- Single or multiple sequential urine samples (90 -110ml or 24 hour urine collection) for cfDNA mutation analysis were obtained at baseline and during therapy.
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Longitudinal Assessment of cfDNA Mutations
- Detection of actionable BRAF and KRAS mutations with droplet digital PCR in urinary cfDNA from patients with advanced cancers is feasible with good preliminary concordance with mutation testing of tumor tissue in the CLIA laboratory.
- BRAF mutations were detected in urine from patients with Erdheim-Chester disease including patients who did not have adequate tissue for molecular analysis.
- Mutations in urine cfDNA should be further investigated for longitudinal assessment of effects of anticancer therapies.