BRAF V600

NOTE: Our laboratory offers multiple testing options for melanoma. Please see our melanoma overview page.

OVERVIEW

The BRAF protein kinase is a component of the RAS/RAF/MAPK pathway which is involved in cell proliferation, differentiation, survival, and apoptosis.  Activating BRAF mutations lead to unrestrained cell growth and proliferation, and are frequent in a variety of solid and hematologic tumours.  More than thirty activating BRAF mutations have been characterized, however those at the V600 codon are the most common.  

Patients with activating mutations at codon V600 may benefit from BRAF inhibitor therapy and/or demonstrate resistance to anti-EGFR or other targeted therapies.  The presence of a BRAF V600 mutation may also have prognostic or diagnostic significance.  In MLH1/PMS2-deficient colorectal cancers, BRAF V600 testing may be useful as a pre-screen prior to Lynch Syndrome testing.

INDICATION

  • Melanoma (non-resectable, metastatic)
  • Colorectal cancer (metastatic, MLH1-deficient and PMS2-deficient, BRAF IHC equivocal or unknown)
  • With prior lab approval, other indications including:
    • Langerhans Cell Histiocytosis
    • Anaplastic Thyroid Carcinoma
    • Hairy Cell Leukemia
    • Erdheim-Chester Disease
    • Cholangiocarcinoma

TEST REQUIREMENTS

  1. Completed CGL Solid Tumour Testing requisition form
    • Select “BRAF (V600 E, D, K)”
  2. FFPE Tumour specimen (seeĀ Specimen Guidelines)
    • A minimum of 10% tumour content is required

TURN-AROUND TIME

Fourteen calendar days from receipt of specimen and completed, signed requisition form.

RESULTS REPORTING

  • Results are reported as positive or negative for the presence of a BRAF V600 mutation (any one of V600E, V600K or V600D). 
  • Specimens with inadequate tumour tissue may be cancelled by the reviewing pathologist prior to receipt in CGL.

METHOD

Tumour tissue is isolated from the FFPE specimen by macrodissection, followed by extraction of genomic DNA (Promega Maxwell).  Analysis of BRAF codon 600 is performed by quantitative PCR using LNA bearing allele specific PCR amplification primers. This assay can reliably detect BRAF V600E, V600K, and V600D mutations; however, the specific mutation cannot be distinguished. The limit of reliable detection of this assay is approximately 1%.

REFERENCES

  1. Holderfield et al. Nature Reviews Cancer (2014) PMID:24957944
  2. Dankner et al. Oncogene (2018) PMID:29540830