Routine sequencing of BRAF exon 15 improves therapeutic stratification for metastatic melanoma

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• BRAF V600E/K mutations drive metastatic melanoma, with targeted therapies improving survival.
• Non-V600E/K BRAF mutations may also respond to MEK-inhibitor therapies.
• These alternative mutations are often unassessed in standard clinical workups.

Purpose of the Study:

• To determine the prevalence and characteristics of BRAF non-V600E/K mutations in metastatic melanoma.
• To evaluate the potential for improved patient stratification using comprehensive BRAF mutation profiling.
• To assess the clinical utility of identifying non-V600E/K BRAF mutations for targeted therapy selection.

Main Methods:

• DNA extraction from 99 metastatic melanoma patient specimens (June 2019 - September 2021).
• Next-generation sequencing (NGS) analysis of BRAF exon 15 to identify mutations.
• Assessment of identified mutations for susceptibility to targeted MEK therapies.

Main Results:

• BRAF non-V600E/K mutations were found in 11% of analyzed specimens.
• All identified non-V600E/K mutations demonstrated prior evidence of susceptibility to MEK-targeted therapies.
• Fewer than half of patients with these susceptible mutations received MEK-targeted therapy.

Conclusions:

• Next-generation sequencing effectively profiles BRAF exon 15 mutations, including those missed by other methods.
• Routine sequencing of BRAF exon 15 is recommended to enhance patient stratification for targeted treatments.
• Identifying non-V600E/K BRAF mutations can optimize therapeutic strategies in metastatic melanoma.