Detecting molecular markers associated with response or resistance to specific cancer
Test Id | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
SLIRV | Slide Review in MG | No, (Bill Only) | Yes |
When this test is ordered, slide review will always be performed at an additional charge.
Digital Droplet Polymerase Chain Reaction (ddPCR)
Cetuximab (Erbitux)
Colorectal cancer
CRC
EGFR
Epidermal growth factor receptor
Erbitux (Cetuximab)
KRAS
KRAS codon 12
KRAS codon 13
KRAS codon 146
KRAS codon 61
KRAS G12C
KRAS WT
Non-small cell lung cancer
NSCLC
Patiumumab (Vectibix)
RAS
Vectibix (Patiumumab)
When this test is ordered, slide review will always be performed at an additional charge.
Varies
Pathology report (final or preliminary) must accompany specimen in order for testing to be performed. At minimum, it should contain the following information:
1. Patient name
2. Block number-must be on all blocks, slides and paperwork (can be handwritten on the paperwork)
3. Tissue collection date
4. Source of the tissue
Preferred:
Specimen Type: Tissue
Container/Tube: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block.
Acceptable:
Specimen Type: Tissue
Container/Tube: Slides
Specimen Volume: 1 stained and 5 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 5 unstained, nonbaked slides with 5-micron thick sections of the tumor tissue.
Specimen Type: Cytology slide (direct smears or ThinPrep)
Slides: 1 to 3 slides
Collection Instructions: Submit 1 to 3 slides stained and coverslipped with a preferred total of 5000 nucleated cells or a minimum of at least 3000 nucleated cells.
Note: Glass coverslips are preferred; plastic coverslips are acceptable but will result in longer turnaround times.
Additional Information: Cytology slides will not be returned.
1. Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519) in Special Instructions.
2. If not ordering electronically, complete, print, and send a Oncology Test Request (T729) with the specimen.
Formalin-fixed, paraffin-embedded (FFPE) tissue block (preferred) or 1 slide stained with hematoxylin and eosin and 5 unstained, nonbaked slides (5-microns thick sections) of the tumor tissue.
Specimens that have been decalcified (all methods) Specimens that have not been formalin- fixed, paraffin-embedded | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Ambient (preferred) | ||
Refrigerated |
Detecting molecular markers associated with response or resistance to specific cancer
When this test is ordered, slide review will always be performed at an additional charge.
Strategies that focus on early detection and prevention effectively decrease the risk of mortality associated with cancer. In addition, an increase in survival rate for individuals with advanced stage disease has been observed as a result of advancements in standard chemotherapeutic agents and the development of specialized targeted therapies. Monoclonal antibodies against epidermal growth factor receptor (EGFR), such as cetuximab and panitumumab, represent an area of targeted therapy for patients with colorectal and non-small cell lung cancer (NSCLC). However, studies have shown that not all individuals with colorectal cancer or NSCLC respond to EGFR targeted molecules. Because the combination of targeted therapy and standard chemotherapy leads to an increase in toxicity and cost, strategies that help to identify the individuals most likely to benefit from such targeted therapies are desirable.
EGFR is a growth factor receptor that 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 cancer, in particular, colorectal cancer and NSCLC.
One of the most common somatic alterations in colon cancer and NSCLC is the presence of activating variants in the protooncogene KRAS. KRAS is recruited by ligand-bound (active) EGFR to initiate the signaling cascade induced by the RAS/MAPK pathway. Because altered KRAS constitutively activates the RAS/MAPK pathway downstream of EGFR, agents such as cetuximab and panitumumab, which prevent ligand-binding to EGFR, do not appear to have any meaningful inhibitor activity on cell proliferation in the presence of altered KRAS. Current data suggest that the efficacy of EGFR-targeted therapies in colon cancer and NSCLC is confined to patients with tumors lacking KRAS mutations. An exception is the KRAS G12C variant that is targetable with variant-specific inhibitors.
This test uses DNA extracted from tumor tissue to evaluate for the presence of KRAS (G12A, G12C, G12D, G12R, G12S, G12V, G13D, Q61K, Q61L, Q61R, Q61H, and A146T) variants. A positive result indicates the presence of an activating KRAS mutation and can be a useful marker by which patients are selected for EGFR-targeted therapy.
An interpretive report will be provided.
An interpretative report will be provided.
Not all patients whose tumors have wild-type KRAS respond to epidermal growth factor receptor (EGFR)-targeted therapies.
Rare alterations (ie, polymorphisms) exist that could lead to false-negative or false-positive results.
Test results should be interpreted in 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 possible interpretation. Misinterpretation of results may occur if the information provided is inaccurate or incomplete.
This assay was designed to detect variants in KRAS codons 12, 13, 61, and 146 (G12A, G12C, G12D, G12R, G12S, G12V, G13D, Q61K, Q61L, Q61R, Q61H, and A146T).
This test has not been clinically validated for use as a tool to monitor response to therapy or for early detection of tumors.
This test cannot differentiate between somatic and germline alterations.
1.Allegra CJ, Rumble BR, Hamilton SR, et al: Extended RAS gene mutation testing in metastatic colorectal carcinoma to predict response to anti-epodermal growth factor receptor monoclonal antibody therapy: ASCO Provisional Clinical Opinion update 2015. J Clin Oncol. 2016 Jan 10;34(2):179-185
2.Spano JP, Milano G, Vignot S, Khayat D: Potential predictive markers of response to EGFR-targeted therapies in colorectal cancer. Crit Rev Oncol Hematol. 2008;66:21-30
3.Lam DC: Clinical testing for molecular targets for personalized treatment in lung cancer. Respirology 2013Feb;18(2):233-237
4.Hong DS, Fakih MG, Strickler JH, et al: KRAS G12C inhibition with sotorasib in advanced solid tumors. N Engl J Med. 2020 Sep 24;383(13):1207-1217
A pathology review and macrodissection to enrich for tumor cells is performed prior to DNA extraction.
Digital droplet polymerase chain reaction is used to test for the presence of KRAS codon 12, 13, 61, and 146 variants. (Unpublished Mayo method).
Monday through Friday
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 US Food and Drug Administration.
81275-KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene) (eg, carcinoma) gene analysis, variants in codons 12 and 13
81276-KRAS additional variant(s)
88381-Microdissection, manual
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
KRASP | KRAS Somatic Mutation Analysis | In Process |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
610680 | Result Summary | 50397-9 |
610681 | Result | 82939-0 |
610682 | Interpretation | 69047-9 |
610683 | Specimen | 31208-2 |
610684 | Source | 31208-2 |
610685 | Tissue ID | 80398-1 |
610686 | Released By | 18771-6 |
610687 | Method | 85069-3 |
610688 | Disclaimer | 62364-5 |
614165 | Additional Information | 48767-8 |