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High frequency of BRAF mutations in nevi
Pamela M Pollock1, Ursula L Harper, Katherine S Hansen
1Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, 50 South Drive, Bethesda, Maryland 20892, USA.
Nature Genetics
|November 26, 2002
Summary
BRAF mutations are common in nevi and melanoma, indicating they are an early step in melanocytic neoplasia. However, BRAF mutations alone do not cause melanoma, suggesting other factors are involved in tumor development.
Area of Science:
- Oncology
- Genetics
- Dermatology
Background:
- Melanocytic neoplasia involves genetic mutations.
- The BRAF gene and RAS/RAF/MAPK pathway are implicated in cancer development.
Purpose of the Study:
- To determine the timing of BRAF mutations during the development of melanocytic neoplasia.
- To investigate the role of BRAF mutations in melanoma initiation and progression.
Main Methods:
- Mutation analysis was performed on microdissected samples.
- Samples included melanoma metastases, primary melanomas, and nevi.
Main Results:
- BRAF mutations (V599E) were found in 68% of melanoma metastases.
- BRAF mutations were also present in 80% of primary melanomas.
- Unexpectedly, 82% of nevi also harbored BRAF mutations.
Conclusions:
- Mutational activation of the RAS/RAF/MAPK pathway via BRAF mutations is an early event in melanocytic neoplasia.
- BRAF mutations in nevi are a critical initiating step but are insufficient for melanoma tumorigenesis on their own.