Test Overview
Allele-specific Polymerase Chain Reaction (PCR) with capillary electrophoresis detection.
BRAF gene mutations occur in a variety of human malignancies including approximately 10% of colorectal cancers (CRC), 45% of papillary thyroid carcinomas (PTC), 50% of melanomas, virtually all hairy-cell leukemias (HCL), and 5-10% of gastrointestinal stromal tumors (GIST) that are negative for KIT and PDGFRA mutations. The most common BRAF mutation is the c.1799T>A (V600E) substitution. In CRC, this mutation has been associated with a limited clinical response to epidermal growth factor receptor (EGFR) targeted therapies (cetuximab or panitumumab). As a complement to KRAS mutation analysis, BRAF V600E mutation detection may predict response to these therapies. In addition, BRAF V600E mutations are found in sporadic microsatellite instability high (MSI-H) CRC cases, but not in hereditary non-polyposis colorectal cancers (HNPCC). Therefore, determination of BRAF mutation status may help to differentiate sporadic vs. germline MSI-H colorectal cancers. BRAF V600E mutation testing may also aid in the diagnosis of papillary thyroid carcinoma, since benign thyroid neoplasms are not associated with BRAF mutation. In melanoma, the V600E and V600K mutations may predict response to BRAF targeted therapies. This test qualitatively detects the BRAF c.1799T>A (V600E) and BRAF c.1798_1799GT>AA (V600K) mutations in formalin fixed paraffin-embedded tissues, fresh/frozen tissue, peripheral blood, and bone marrow. BRAF mutations other than V600E and V600K will not be detected. Analytic sensitivity is 5% mutation.
Interpretive report provided.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
This test will only detect the c.1799T>A (V600E) and c.1798_1799GT>AA (V600K) mutations. Other rare BRAF mutations will not be detected. A negative result does not rule out the presence of BRAF V600E or V600K mutation below the sensitivity of detection (5% mutant allele).
Test Details
3 - 10 days
- c.1798_1799GT>AA (V600K) Mutation
- c.1799T>A (V600E) Mutation
Specimen Requirements
Collect blood or bone marrow in a lavender top tube. Refrigerate and send intact blood or bone marrow specimen within 48 hours of collection. Fresh tissue (preferably 0.5cm3, sent in RPMI) and fresh aspirates or body fluids are acceptable. Refrigerate and send, preferably within 24 hours. Frozen tissue specimens – preferably frozen with 1 hour of collection – may also be sent frozen on dry ice. Fresh cell suspensions in RPMI should be refrigerated and sent, preferably within 48 hours. Frozen cell suspensions – preferably frozen with 1 hour of collection – may also be sent frozen on dry ice. For formalin-fixed, paraffin-embedded tissue, a block containing an area with a high percentage of neoplastic cells (for micro-/macro-dissection) is preferred. Unstained, UNBAKED slides (5-8, 10-micron slides; 10-15 if few neoplastic cells are present) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature. A Diff-Quik stained aspirate smear (preferable containing a high percentage and overall amount of neoplastic cells) is also acceptable. Store at room temperature.
Additional Information
By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test may include microdissection billed as a separate additional charge. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.