Braf Codon 600 – Colon Cancer

 
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BRAF CODON 600 – COLON CANCER

 
Gene Symbol: BRAF                            
Chromosomal Locus: 7q34
 
Protein: v-raf Murine Sarcoma Viral Oncogene Homolog B1      
 
TURNAROUND TIME: 8 days.
  
TESTING METHODOLOGY:  Polymerase chain reaction (PCR) and Shifted Termination Assay for detection of specific mutations.  Mutations detected are V600E (GTGGCG), and V600G (GTG>GGG).
 
SPECIMEN REQUIREMENTS:
 
Collect:  FFPE tumor specimen containing at least 30% tumor mass. 5 to 6 unstained slides with 3-4 um thick tissue sections.  Must be accompanied by a pathology report and an H&E slide with the tumor regions identified.
  • Transport: Specimen should be shipped at Room Temperature (No Saturday delivery
  • Unacceptable Conditions: Stained slides.        
Molecular Genetics Laboratory Test Requisition must accompany the specimen. Contact the Molecular Laboratory at 918-502-1721 to obtain further information.
 
Note: Counseling and informed consent are recommended for genetic testing. A consent form is available as a resource but not required.
 
INTERPRETATIVE DATA:
 
Incidence:  Found in 10-12% of all colorectal tumors.
 
Indications for Testing:  BRAF mutations at codon 600 are present in 6-10% of colon cancers that are normal for the KRAS gene at codons 12 and 13.  Tumors that have a BRAF mutation will not respond to anti-EGFR inhibitor drugs. KRAS and BRAF mutations are mutually exclusive.
 
Molecular Genetic Mechanism:  The BRAF V600E mutation enhances the proliferation and metastasis of tumor cells.
 
Related Tests: KRAS, EGFR 
 
Clinical Sensitivity: The tissue sample submitted for testing must contain at least 30% tumor.  The assay will detect as low as a 5% population of mutant cells.
 
Analytical Sensitivity: 95%
 
Test Limitations: Mutations not listed in the methodology will not be detected.   This test is only for somatic BRAF changes in cancer tissues.  Rare diagnostic errors can occur due to primer / probe site mutations or rare polymorphisms.
 
INDICATIONS FOR USE:  
  • To assess the potential effectiveness of anti - EGFR therapies.
  • Detection of the BRAF V600 mutations prior to expensive screening of the MMR genes.
  • To determine whether a patient might be a candidate for BRAF kinase inhibitors.
ADDITIONAL REFERENCES: 
Genetics Home Reference:  www.ghr.nlm.nih.gov/gene/BRAF