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Test Code RASFP RAS/RAF Targeted Gene Panel by Next-Generation Sequencing, Tumor

Useful For

Identifying tumors that may respond to targeted therapies by assessing multiple gene targets simultaneously

 

Identifying mutations that may help determine prognosis for patients with solid tumors

 

Identifying specific mutations within genes known to be associated with response or resistance to specific cancer therapies

Genetics Test Information

This extended RAS/RAF panel test uses targeted next-generation sequencing to evaluate for somatic mutations within the BRAF (exons 11 and 15), HRAS (exons 2 and 3), NRAS (exons 2, 3, 4), and KRAS (exons 2, 3, 4) genes. This includes, but is not limited to, the testing of somatic mutations in KRAS codons 12, 13, 59, 61, 117, 146; NRAS codons 12, 13, 59, 61,146; HRAS codons 12, 13, 61; and BRAF codons 594, 596, 600. See Targeted Gene Regions Interrogated by RAS/RAF Gene Panel in Special Instructions for details regarding the targeted gene regions identified by this test.

 

Of note, this test is performed to evaluate for somatic mutations within tumor samples. This test does not assess for germline alterations within the genes listed.

Additional Tests

Test ID Reporting Name Available Separately Always Performed
SLIRV Slide Review in MG No Yes

Testing Algorithm

When this test is ordered, slide review will always be performed at an additional charge.

Method Name

Polymerase Chain Reaction (PCR)-Based Next Generation Sequencing

Reporting Name

RAS/RAF Panel, Tumor

Specimen Type

Varies


Advisory Information


At least 20% tumor is required for this assay. The amount of tissue needed is dependent on a variety of preanalytical factors (eg, cellularity, ischemic time, fixation). In general, the minimum specimen adequacy for this test is approximately a 6 mm(2) area of tissue (can be over multiple slides from one tissue block) or 5,000 total cells (5,000 total nucleated cells if using cytology slides).



Necessary Information


A pathology report must accompany specimen in order for testing to be performed.



Specimen Required


Preferred:

Specimen Type: Tissue

Container/Tube: Tissue block

Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block.

 

Acceptable:

Specimen Type: Tissue

Slides: 1 stained and 10 unstained

Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, unbaked slides with 5-micron thick sections of the tumor tissue.

 

Acceptable:

Specimen Type: Cytology

Container/Tube: Cytology slide (Direct smears or ThinPrep)

Slides: 1-2 slides (stained and coverslipped) with a minimum of 5,000 total nucleated cells

Collection Instructions: Submit 1-2 slides stained and coverslipped.

Additional Information: Cytology slides will not be returned.


Specimen Minimum Volume

Formalin-fixed, paraffin-embedded (FFPE) tissue block (preferred) or 1 slide stained with hematoxylin and eosin and 8 unstained, nonbaked slides

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Reject Due To

No specimen should be rejected.

Clinical Information

Targeted cancer therapies are defined as antibody or small molecule drugs that block the growth and spread of cancer by interfering with specific cell molecules involved in tumor growth and progression. Multiple targeted therapies have been approved by the US Food and Drug Administration (FDA) for treatment of specific cancers. Molecular genetic profiling is often needed to identify targets amenable to targeted therapies and to minimize treatment costs and therapy-associated risks.

 

Next generation sequencing has recently emerged as an accurate, cost-effective method to identify mutations across numerous genes known to be associated with response or resistance to specific targeted therapies. The results of this test can be useful for assessing prognosis and guiding treatment of individuals with solid tumors. These data can also be used to help determine clinical trial eligibility for patients with mutations in genes not amenable to current FDA-approved targeted therapies.

 

The epidermal growth factor receptor (EGFR) gene product is activated by the binding of specific ligands (epiregulin and amphiregulin), resulting in activation of the RAS/MAPK pathway. Activation of this pathway induces a signaling cascade ultimately regulating a number of cellular processes including cell proliferation. Dysregulation of the RAS/MAPK pathway is a key factor in tumor progression. Targeted therapies directed to EGFR, which inhibit activation of the RAS/MAPK pathway, have demonstrated some success (increased progression-free and overall survival) in patients with colorectal cancer.

 

Assessment for BRAF mutations has clinical utility in that it is a predictor of response to antimutant BRAF therapy. BRAF is a member of the mitogen-activated protein/extracellular signal-regulated (MAP/ERK) kinase pathway, which plays a role in cell proliferation and differentiation. Dysregulation of this pathway is a key factor in tumor progression. Targeted therapies directed to components of this pathway have demonstrated some success with increases both in progression-free and overall survival in patients with certain tumors. Effectiveness of these therapies, however, depends in part on the mutation status of the pathway components.

 

See Targeted Gene Regions Interrogated by RAS/RAF Gene Panel in Special Instructions for details regarding the targeted gene regions identified by this test.

Reference Values

An interpretive report will be provided.

Interpretation

An interpretive report will be provided.

Cautions

This test cannot differentiate between somatic and germline alterations. Additional testing may be necessary to clarify the significance of results if there is a potential hereditary risk.

 

DNA variants of uncertain significance may be identified.

 

A negative (wild-type) result does not rule out the presence of a mutation that may be present but below the limits of detection of this assay (approximately 5%-10%).

 

This test does not detect large single or multiexon deletions or duplications or genomic copy number variants.

 

Rare polymorphisms may be present that could lead to false-negative or false-positive results. Test results should be interpreted in the context of clinical findings, tumor sampling, and other laboratory data. If results obtained do not match other clinical or laboratory findings, please contact the laboratory for updated interpretation. Misinterpretation of results may occur if the information provided is inaccurate or incomplete.

Clinical Reference

1. Targeted Cancer Therapies. National Cancer Institute Fact Sheet. Updated 12/05/2012. Accessed December 2013, Available at www.cancer.gov/cancertopics/factsheet/Therapy/targeted

2. Vogelstein B, Papadopoulos N, Velculescu VE, et al: Cancer genome landscapes. Science 2013;339:1546-1558

3. Beadling C, Neff TL, Heinrich MC, et al: Combining highly multiplexed PCR with semiconductor-based sequencing for rapid cancer genotyping. J Mol Diagn 2013;15:171-176

4. Anderson S, Bloom KJ, Vallera DU, et al: Multisite analytic performance studies of a real-time polymerase chain reaction assay for the detection of BRAF V600E mutations in formalin-fixed paraffin-embedded tissue specimens of malignant melanoma. Arch Pathol Lab Med 2012 Feb;136:1-7

5. Di Nicolantonio F, Martini M, Molinari F, et al: Wild-type BRAF is required for response to Panitumumab or Cetuximab in metastatic colorectal cancer. J Clin Oncol 2008;26:5705-5712

6. Flaherty KT, Puzanov I, Kim KB, et al: Inhibition of mutated, activated BRAF in metastatic melanoma. N Engl J Med 2010;363(9):809-819

7. Ladanyi M, Pao W: Lung adenocarcinoma: guiding EGFR-targeted therapy and beyond. Mod Pathol 2008;21 Suppl 2:S16-S22

8. Lievre A, Bachet JB, Le Corre D, et al: KRAS mutation status is predictive of response to Cetuximab therapy in colorectal cancer. Cancer Res 2006;66(8):3992-3995

Method Description

Next-generation sequencing is performed to test for the presence of a mutation in targeted regions of the following 4 genes: BRAF, HRAS, NRAS, KRAS.(Unpublished Mayo method)

 

See Targeted Gene Regions Interrogated by RAS/RAF Gene Panel in Special Instructions for details regarding the targeted gene regions identified by this test.

Day(s) and Time(s) Performed

Monday through Friday; Varies

Analytic Time

12 days

Specimen Retention Time

Unused portions of blocks will be returned. Unused slides are stored indefinitely.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

RAS/RAF Targeted Gene Panel by Next Generation Sequencing, Tumor

81210-BRAF (v-raf murine sarcoma viarl oncogene humolog B1) (eg, colon cancer), gene analysis, V600E variant

81275-KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene) (eg, carcinoma) gene analysis, variants in codons 12 and 13

81403-HRAS (v-Ha-ras Harvey rat sarcoma viral oncogene homolog) (eg, Costello syndrome), exon 2 sequence

81404-NRAS (neuroblastoma RAS viral oncogene homolog) (eg, colorectal carcinoma), exon 1 and exon 2 sequence

Slide Review

88381-Microdissection, manual

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RASFP RAS/RAF Panel, Tumor In Process

 

Result ID Test Result Name Result LOINC Value
36725 Result Summary 50397-9
36726 Result No LOINC Needed
36727 Interpretation 69047-9
36728 Additional Information 48767-8
36729 Specimen 31208-2
36730 Source 31208-2
36731 Tissue ID In Process
36732 Released By In Process

Forms

If not ordering electronically, complete, print, and send an Oncology Test Request Form (T729) with the specimen (http://www.mayomedicallaboratories.com/it-mmfiles/oncology-request-form.pdf)