There are key genes recurrently mutated in colorectal cancer. Genomic DNA is isolated from formalin fixed paraffin embedded tissue and the DNA sequence of targeted regions of the BRAF, KRAS, and NRAS genes is determined using next-generation sequencing (NGS) technology.
For Predictive, Prognostic purposes.
NCCN Guidelines recommend testing for RAS (both KRAS and NRAS) and BRAF mutations in all patients with metastatic colorectal cancer. Mutations in codons 12 and 13 of the KRAS gene are found in ~40% of colorectal cancers. Up to another 20% of tumors harbor mutations in other codons/exons of KRAS, or in NRAS. Pathogenic KRAS and NRAS mutations predict a lack of response to anti-EGFR antibody therapies such as cetuximab and panitumumab. The BRAF c.1799T>A; p.V600E mutation confers a poor prognosis irrespective of treatment, and may be associated with high-risk disease features. There is also a growing body of evidence that this BRAF mutation may be predictive of a lack of response to anti-EGFR antibody therapies, in both first- and second-line settings.
- Tissue (Preferred): Two (2) formalin-fixed, paraffin-embedded tissue/ fine needle aspirate (FFPE/FNA) blocks containing tumor tissue from recent surgery or biopsy or sixteen (16) 2x5 µm sections with accompanying H&E slide.
- Acceptable Alternative: One (1) formalin-fixed, paraffin-embedded tissue/fine needle aspirate (FFPE/FNA) block containing tumor tissue from recent surgery or biopsy or eight (8) 2×5 µm sections with accompanying H&E slide.
- Unacceptable: Specimens preserved in alternative (non-formalin) fixatives, decalcified specimens, fresh or frozen tissue.
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. DO NOT FREEZE.