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HelpTest Code MCGST MayoComplete Gastrointestinal Stromal Tumor (GIST) Panel, Next-Generation Sequencing, Tumor
Ordering Guidance
Multiple oncology (cancer) gene panels are available. For more information see Hematology, Oncology, and Hereditary Test Selection Guide.
Necessary Information
A pathology report (final or preliminary), at minimum containing the following information, must accompany specimen for testing to be performed:
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
Specimen Required
This assay requires at least 20% tumor nuclei.
-Preferred amount of tumor area with sufficient percent tumor nuclei: tissue 216 mm(2)
-Minimum amount of tumor area: tissue 36 mm(2)
-These amounts are cumulative over up to 10 unstained slides and must have adequate percent tumor nuclei.
-Tissue fixation: 10% neutral buffered formalin, not decalcified
-For specimen preparation guidance, see Tissue Requirement for Solid Tumor Next-Generation Sequencing. In this document, the sizes are given as 4 mm x 4 mm x 10 slides as preferred: approximate/equivalent to 144 mm(2) and the minimum as 3 mm x 1 mm x 10 slides: approximate/equivalent to 36 mm(2).
Preferred:
Specimen Type: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block with acceptable amount of tumor tissue.
Acceptable:
Specimen Type: Tissue slides
Slides: 1 Stained and 10 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, nonbaked slides with 5-micron thick sections of the tumor tissue.
Note: The total amount of required tumor nuclei can be obtained by scraping up to 10 slides from the same block.
Additional Information: Unused unstained slides will not be returned.
Specimen Type: Cytology slides (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.
Secondary ID
616490Useful For
Establishing diagnosis and identifying targeted therapies for patients with gastrointestinal stromal tumors
Assessing microsatellite instability
Highlights
This test evaluates formalin-fixed, paraffin-embedded tumor or cytology slides from patients with gastrointestinal stromal tumors for gene mutations to identify candidates for targeted therapy.
Microsatellite instability (MSI) status is also determined (microsatellite stable, MSI-High) as part of this test and is often clinically actionable for determining the efficacy of immunotherapy in solid tumors.
Additional Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SLIRV | Slide Review in MG | No, (Bill Only) | Yes |
Testing Algorithm
When this test is ordered, slide review will always be performed at an additional charge.
Special Instructions
Method Name
Sequence Capture and Targeted Next-Generation Sequencing (NGS)
Reporting Name
MayoComplete GIST PanelSpecimen Type
VariesSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Refrigerated | |||
Reject Due To
| Specimens that have been decalcified (all methods) Specimens that have not been formalin-fixed, paraffin-embedded, except for cytology slides Extracted nucleic acid (DNA/RNA) |
Reject |
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 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. Microsatellite instability status is an important biomarker for determining effective immunotherapeutic treatment options for patients with solid tumors.
Next-generation sequencing is an accurate, cost-effective method to identify mutations across numerous genes known to be associated with response or resistance to specific targeted therapies. This test is a single assay that uses formalin-fixed paraffin-embedded tissue to assess for common mutations in the following genes known to be associated with gastrointestinal stromal tumors (GIST): APC, BRAF, HRAS, KIT, KRAS, NF1, NRAS, PDGFRA, PIK3CA, SETD2, and TP53. The results of this test can be useful for assessing prognosis and guiding treatment of individuals with GIST.
Reference Values
An interpretive report will be provided.
Interpretation
The interpretation of molecular biomarker analysis includes an overview of the results and the associated diagnostic, prognostic, and therapeutic implications.
Method Description
Next-generation sequencing is performed to determine microsatellite instability status and evaluate the presence of a mutation in all coding regions of the APC, BRAF, HRAS, KIT, KRAS, NF1, NRAS, PDGFRA, PIK3CA, SETD2, and TP53 genes. See Targeted Genes and Methodology Details for MayoComplete Gastrointestinal Stromal Tumor Panel for details regarding the targeted gene regions evaluated by this test.(Unpublished Mayo method)
A pathology review and macro dissection to enrich for tumor cells are performed prior to slide scraping.
Day(s) Performed
Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
88381-Microdissection, manual
81457
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MCGST | MayoComplete GIST Panel | 102117-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 617873 | Result | 82939-0 |
| 617874 | Interpretation | 69047-9 |
| 617875 | Additional Information | 48767-8 |
| 617876 | Specimen | 31208-2 |
| 617877 | Tissue ID | 80398-1 |
| 617878 | Method | 85069-3 |
| 617879 | Disclaimer | 62364-5 |
| 617880 | Released By | 18771-6 |
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.