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Updated: May 16, 2026
Employing Digital Droplet PCR to Detect BRAF V600E Mutations in Formalin-fixed Paraffin-embedded Reference Standard Cell Lines
Published on: October 8, 2015
Evaluation of BRAF mutation testing methodologies in formalin-fixed, paraffin-embedded cutaneous melanomas
Johanne Lade-Keller1, Kirsten M Rømer, Per Guldberg
1Institute of Pathology, Aarhus University Hospital, Aarhus, Denmark. johanneromer@hotmail.com
Abstract:
Patients diagnosed with BRAF V600E mutated cutaneous melanoma show response to treatment with the BRAF inhibitor Vemurafenib. Different methods for BRAF mutation detection exist; however, only the Cobas 4800 BRAF V600 Mutation Test has been approved by the US Food and Drug Administration for patient selection. The results from this test depend on the percentage of tumor cells in the samples, which clinically may be estimated with substantial variation. We have evaluated five different methods: the Cobas test, Sanger sequencing, pyrosequencing, TaqMan-based allele-specific PCR, and Competitive Amplification of Differentially Melting Amplicons (CADMA), for detection of BRAF c.1799T>A (V600E) mutations in 28 formalin-fixed paraffin-embedded (FFPE) cutaneous melanoma samples. We show that the frequency of the BRAF V600E mutation is influenced by the analytical sensitivity of the applied method. However, a 100% consensus was observed among all five methods when the tumor tissue fraction was more than 10% of all tissue or more than 50% of cell-dense tissue. When using Sanger sequencing, pyrosequencing, or the Cobas test, it may be advisable to perform macrodissection before mutation testing if the tumor cell fraction is low. CADMA and TaqMan may not require macrodissections for a reliable test. Therefore, the use of more sensitive methods may have a future in testing for BRAF mutations in clinical settings.
Insights
Accurate BRAF V600E mutation detection in cutaneous melanoma is crucial for Vemurafenib treatment. Five methods showed consensus above 10% tumor cells, but sensitive techniques like CADMA and TaqMan may avoid macrodissection for reliable results.
Area of Science:
- Oncology
- Molecular Diagnostics
- Genetics
Background:
- Cutaneous melanoma patients with BRAF V600E mutations respond to BRAF inhibitor Vemurafenib.
- The Cobas 4800 test is FDA-approved for patient selection, but results are sensitive to tumor cell percentage.
- Tumor cell percentage estimation in samples can vary significantly.
Purpose of the Study:
- To evaluate five different methods for detecting BRAF c.1799T>A (V600E) mutations in melanoma samples.
- To assess the impact of analytical sensitivity and tumor cell fraction on mutation detection.
- To determine the reliability of different methods, with or without macrodissection, for clinical application.
Main Methods:
- Comparison of Cobas test, Sanger sequencing, pyrosequencing, TaqMan-based PCR, and Competitive Amplification of Differentially Melting Amplicons (CADMA).
- Testing on 28 formalin-fixed paraffin-embedded (FFPE) cutaneous melanoma samples.
- Analysis of mutation detection rates based on varying tumor cell percentages.
Main Results:
- Mutation detection frequency varied based on the analytical sensitivity of each method.
- All five methods achieved 100% consensus when tumor tissue fraction exceeded 10% (or 50% of cell-dense tissue).
- Sanger sequencing, pyrosequencing, and Cobas test may require macrodissection for low tumor cell fractions, unlike CADMA and TaqMan.
Conclusions:
- Analytical sensitivity influences BRAF V600E mutation detection frequency.
- More sensitive methods like CADMA and TaqMan may offer reliable detection without macrodissection, even with low tumor cell content.
- Advanced detection methods hold promise for improved BRAF mutation testing in clinical melanoma management.
