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BRAF V600E Mutation Analysis

BRAF, colon cancer, melanoma, papillary thyroid, non-small cell lung cancer

Test Codes

V600E, SOFTPATH: MBRFG, SOFTLAB: MBRFG, SOFTMOL: MBRF

Department

Molecular Pathology

Specimen Collection Criteria

Collect: Paraffin-embedded tissue. A paraffin block must be submitted. (Slides or paraffin shavings are not acceptable.) Submit formalin-fixed, paraffin-embedded block with corresponding H&E slide. Tissue should be well fixed and well processed. Average tissue size 5.0 mm².

• DNA will be assessed for quality. If it is deemed unacceptable, testing will be cancelled with client notification. 
• The specimen must be accompanied by a completed requisition and must contain the patient name, date of birth, collection date, ordering physician, and source of specimen.   

Physician Office/Draw Specimen Preparation

Maintain paraffin-embedded tissue at room temperature (20-26°C or 68-78.8°F) until transport. 

Preparation for Courier Transport

Transport: Paraffin-embedded tissue, at room temperature (20-26°C or 68-78.8°F). 

Rejection Criteria

• Tissue decalcified in agents other than Mol decal (EDTA)Fixatives other than 10% neutral buffered formalin (e.g. alcohol, zinc formalin).
• Improper labeling or inadequate information.  
• Less than 10 percent tumor cellularity, at discretion of medical director. 
• Poor quality and/or quantity of extracted genomic DNA. 

Testing will be cancelled on specimens meeting the above criteria with client notification 

Inpatient Specimen Preparation

Specimens at Royal Oak may be sent to the Surgical Pathology tube station, #201. In-house specimens are also picked up by a Surgical Pathology assistant every hour on the hour. 

In-Lab Processing

Maintain specimens at room temperature (20-26°C or 68-78.8°F) until testing. 

Storage

Specimen Stability for Testing: 

Room Temperature (20-26°C or 68-78.8°F): Indefinitely
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal: 

Room Temperature (20-26°C or 68-78.8°F): 7 days 

Laboratory

Royal Oak Clinical Molecular Pathology Laboratory

Performed

Once per week.
Results available in 10 business days. 

Reference Range

No BRAF mutations detected. 

Test Methodology

Tissue sections are reviewed by a pathologist and relevant tumor is selected for analysis. DNA is isolated from the sample and quantified. The DNA is amplified using reagents supplied in a BRAF mutation detection kit (EntroGen, Inc., Tarzana CA). The samples are analyzed using an ABI 7500 FAST Real-Time PCR Instrument (Applied Biosystems Inc, Foster City, CA). False positive or negative results may occur for reasons that include genetic variants or somatic heterogeneity of the tissue sample. 

Interpretation

• Negative; No BRAF mutation detected.
• Positive; BRAF V600E mutation detected.

NOTE: This test is only designed to detect the BRAF V600E variant. Other V600 mutations may occasionally be detected due to cross reactivity. 

Clinical Utility

• The BRAF gene is a key component of the EGFR signal transduction pathway. 
• Activating mutations in codon 600 of the BRAF gene have been described in a number of cancers including colorectal cancer, melanoma, non-small cell lung cancer (NSCLC) and papillary thyroid cancer.  V600E is the most common BRAF mutation across all tumor types. 
• Studies show that patients with metastatic colorectal cancer (mCRC) whose tumor carries a BRAF mutation have a worse overall prognosis and are less likely to respond anti-EGFR therapy compared with non-mutated tumors. There is also an association of this mutation with acquired, rather than germline microsatellite instability in MSI-H colorectal cancer. More recently, there has been emerging data indicating modest benefit of combined BRAF/EGFR/MEK inhibitors in V600E mCRC.  
• Patients with advanced melanoma containing a BRAF mutation are likely to benefit from treatment with BRAF inhibitor drugs such as Vemurafenib. 
• In June 2017 the FDA granted regular approval for combined dabrafenib/trametinib therapy for metastatic non-small cell lung cancer (NSCLC) with BRAF V600E mutation. 
• BRAF mutations occur in a majority of childhood gliomas, where they portend a better prognosis and responsiveness to BRAF inhibitors. 
• BRAF mutations occur in 40-45% of papillary thyroid carcinoma, where they are associated with more aggressive behavior but also responsiveness to BRAF inhibitors. 
• Rare cases of BRAF-mutated gastrointestinal stromal tumors (GISTs) are associated with resistance to imatinib and sunitnib but potential responsiveness to BRAF inhibitors. 
• Emerging data have also suggested that cases of anaplastic thyroid carcinoma, cholangiocarcinoma, Erdheim-Chester disease, and Langerhan’s cell histiocytosis with BRAF mutations respond positively to combined BRAF and MEK inhibition.
• Patients with metastatic colorectal carcinomas, advanced melanoma, and metastatic NSCLC should be tested for BRAF mutations to predict responsiveness to targeted inhibitor therapy. BRAF mutation in metastatic colorectal cancer is also a biomarker for non-responsiveness to cetuximab and panitumamab and is helpful in cases of MSI-H tumors where MLH promoter methylation is negative, as a positive result is suggestive of sporadic MSI. BRAF mutation can be helpful with prediction of response to targeted agents in thyroid carcinoma, pediatric glioma, and GIST. Other indications are assessed on a case-by-case basis.  

CPT Codes

81210

Contacts

Last Updated

4/8/2024