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HelpTest ID GISTP GIST Targeted Gene Panel by Next Generation Sequencing, Tumor
Useful For
Diagnosis and management of patients with gastrointestinal stromal tumors (GIST)
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
PCR-Based Next Generation Sequencing
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)
Reporting Name
GIST Panel, TumorSpecimen Type
VariesPathology report must accompany specimen in order for testing to be performed.
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)
Preferred:
Specimen Type: Tissue
Container/Tube: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block.
Additional 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) or 5000 total cells.
Acceptable:
Specimen Type: Tissue
Container/Tube: Slides
Specimen Volume: 1 stained and 10 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, non-baked slides with 5-micron thick sections of the tumor tissue.
Additional 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) or 5000 total cells.
Specimen Type: Cytology
Container/Tube: Cytology slide (Direct smears or ThinPrep)
Specimen Volume: 1 to 2 slides (stained and coverslipped) with a minimum of 5000 total nucleated cells
Collection Instructions: Submit 1 to 2 slides stained and coverslipped
Additional Information: At least 20% tumor is required for this assay. The amount of cells needed is dependent on a variety of preanalytical factors (eg, cellularity, ischemic time, fixation), but the minimum specimen requirement is 5000 total nucleated cells if using cytology slides. 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 10 unstained, non-baked slides with 5-microns thick sections of the tumor tissue with at least 6 mm(2) area of tissue (can be over multiple slides) and 20% tumor nuclei, 1 stained and coverslipped cytology slide with at least 5000 total nucleated cells and at least 20% tumor cells
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Ambient (preferred) | |
| Frozen | ||
| Refrigerated | ||
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 United States 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. GISTP / GIST Targeted Gene Panel by Next Generation Sequencing, Tumor is a single assay that uses formalin-fixed paraffin-embedded tissue to assess for common mutations in the KIT and PDGFRA genes known to be associated with gastrointestinal stromal tumors (GIST). The results of this test can be useful for assessing prognosis and guiding treatment of individuals with GIST.
See Targeted Gene Regions Interrogated by Solid Tumor Targeted Cancer Gene Panel by Next Generation Sequencing in Special Instructions for details regarding the targeted gene regions identified by this test.
Reference Values
An interpretative 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.
Reliable results are dependent on adequate specimen collection and processing. This test has been validated on formalin-fixed, paraffin-embedded tissues; other types of fixatives are discouraged. Improper treatment of tissues, such as decalcification, may cause PCR failure.
KIT mutations can be seen in neoplasms other than gastrointestinal stromal tumors including, but not limited to: mast cell disease, melanoma, seminomas, acute myeloid leukemia, myeloproliferative neoplasms, and some lymphomas.
PDGFRA mutations may be occasionally found in inflammatory fibroid polyps.(1)
For KIT Asp816Val mutation analysis in mast cell disease, refer to KITAS / KIT Asp816Val Mutation Analysis, Qualitative PCR.
Day(s) Performed
Monday through Friday; Varies
Report Available
12 daysPerforming 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
81272-KIT (v-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog) (eg, gastrointestinal stromal tumor [GIST], acute myeloid leukemia, melanoma), gene analysis, targeted sequence analysis (eg, exons 8, 11, 13, 17, 18)
81314-PDGFRA (platelet-derived growth factor receptor alpha polypeptide) (eg, gastrointestinal stromal tumor [GIST]), gene analysis, targeted sequence analysis (eg, exons 12, 18)
88381-Microdissection, manual