RAS-RAF Targeted Mutation Panel

Synonyms

KRAS exon 2, 3, and 4; NRAS exon 2, 3, and 4; BRAF_V600; Colon and Colorectal cancer; Extended RAS Testing

  • Tech Only CPT
  • Tech Pro CPT 81210, 81276, 81275, 81311, 88381, G0452
  • PowerPath Code
  • Schedule Tuesday & Thursday
  • Turn Around Time 4-7 Days
  • Disease State Colon cancer, Melanoma
  • Methodology Real-Time PCR

Specimen Requirements

Specimen Type: FFPE blocks, slides, smear, or Cytospin
Preferred Volume: blocks or slides (1 H&E slide and 4 unstained slides for large tissue section and 20 unstained slides for small biopsies; 4-6 microns)
Minimum Volume: blocks or slides (1 H&E slide and 2 unstained slides for large tissue section and 15 unstained slides for small biopsies; 4-6 microns) EDTA decal specimens are accepted

Clinical Significance

The RAS proto-oncogenes encode a family of GDP/GTP-regulated switches that convey extracellular signals to regulate the growth and survival properties of cells. Mutations which change amino acid residues 12, 13 or 61 activate the potential of K-ras or N-ras are implicated in a variety of human tumors. KRAS mutations have been commonly found in several types of tumor, including pancreatic, colorectal, and non-small-cell lung cancers. NRAS mutations occur in 1-6% of colorectal cancers. Multiple studies have now shown that patients with mutations in KRAS or NRAS are unlikely to benefit from anti-EGFR antibody therapy. The NCCN Colon/Rectal Cancer panel suggests that KRAS mutations (including non-exon 2 mutations) and NRAS mutation status should be determined at diagnosis of stage IV disease. Patients with known KRAS or NRAS mutation should not be treated with either cetuximab or panitumumab. In addition, the NCCN guidelines for non-small cell lung cancer recommended that KRAS gene sequencing could be useful for the selection of patients as candidates for EGFR TKI therapy since KRAS mutations are associated with intrinsic EGFR TKI resistance. The v-raf murine sarcoma viral oncogene homolog B1(BRAF) gene encodes a serine/threonine protein kinase, which plays a key role in regulating MAPK/ERK signaling pathway, affecting cell growth, differentiation and proliferation. Mutations in BRAF have been reported in 80% of melanoma, 5% of colorectal, and 3% of lung cancer. Studies with metastatic colorectal cancer patients have shown resistance to anti-EGFR therapy in tumors positive for BRAF_V600 mutations.

Required Patient Info

Clinical indication; copy of pathology report,specimen source, CBC if available

Storage and Transportation

Room temperature or refrigerated. Ship in cooled container during summer months

Cause for Rejection

Frozen specimen; Acidic delcal specimen; limited cellularity and/or invasive cancer (<10% tumor content)

Retention

1 year

Comments

Limitations:This test only detects targeted 40 mutations in the KRAS-NRAS-BRAF genes and does not detect mutations in other regions of these genes. Results of this test must be interpreted in the context of morphological data and other clinical presentation and should not be used as sole mean of diagnosis of malignancy.Compliance Remarks:This test was developed and its performance characteristics determined by the Molecular Pathology Laboratory, CellNetix Pathology & Laboratories, Seattle WA 98104. It has not been approved by the U.S. Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary. This test is for clinical purposes. It should not be regarded as investigational or for research. This laboratory is regulated under the 1988 CLIA amendments as qualified to perform high-complexity clinical testing.

Vendor

LDT