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HelpTest Code TERTD TERT Promoter Mutation Analysis, Droplet Digital PCR, Tumor
Ordering Guidance
For the preferred test to assess for somatic hotspot mutations in the TERT, IDH1, and IDH2 genes, order IDTRT / IDH1, IDH2 and TERT Mutation Analysis, Next-Generation Sequencing, Tumor.
If this test is ordered with IDHT / IDH1 and IDH2 Mutations Analyses, Next-Generation Sequencing, Tumor, this test will be canceled and ordered as IDTRT.
Necessary Information
1. A pathology report (final or preliminary) is required and must accompany specimen for testing to be performed.
2. The following information must be included in the report provided.
-Patient name
-Block number-must be on all blocks, slides and paperwork (can be handwritten on the paperwork)
-Date of tissue collection
-Source of the tissue
Specimen Required
This assay requires at least 5% nuclei of tumor cells/cells of interest.
-Preferred amount of tumor area with sufficient percent tumor nuclei: tissue144 mm(2)
-These amounts are cumulative over up to 10 unstained slides and must have adequate percent nuclei of tumor cells/cells of interest.
-Tissue fixation: 10% neutral buffered formalin, not decalcified
-Cytology fixatives: Cytology smears fixed in alcohol and thin preps fixed with CytoLyt.
Preferred:
Specimen Type: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block with acceptable percent nuclei of tumor cells/cells of interest.
Acceptable:
Specimen Type: Tissue slides
Slides: 1 Hematoxylin and eosin stained and 10 unstained
Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 10 unstained, nonbaked slides with 5-micron thick sections.
Note: The total amount of required cell nuclei can be obtained by scraping up to 10 slides from the same block.
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 3000 nucleated cells or a minimum of at least 350 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.
Useful For
Identifying specific mutations within the TERT promoter that assist in tumor diagnosis/classification
Genetics Test Information
This test uses droplet digital PCR (ddPCR) to evaluate for the presence of the c.-124C>T (also known as C228T) and c.-146C>T (also known as C250T) somatic mutations in the promoter region of the TERT gene. TERT promoter analysis ddPCR is a highly sensitive testing platform that can detect the c.-124C>T (C228T) and c.-146C>T (C250T) hotspot mutations at low levels, which may be observed in specimens with low number or proportion (%) of tumor cells/cells of interest.
This test cannot differentiate between somatic and germline variant origin and is not intended to assess for germline risk.
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
Droplet Digital Polymerase Chain Reaction (ddPCR)
Reporting Name
TERT Promoter Analysis ddPCR, TumorSpecimen 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 excluding cytology slides Extracted nucleic acid (DNA/RNA) |
Reject |
Clinical Information
The TERT gene encodes the catalytic subunit of telomerase, an enzyme complex that regulates telomere length. Mutations in the TERT promoter, primarily involving mutational hotspot positions c.-124 (also known as C228) and c.-146 (also known as C250), increase telomerase activity allowing tumor cells to overcome cellular senescence. In central nervous system (CNS) tumors, TERT promoter mutations are a diagnostic and grading molecular biomarker in diffuse gliomas and meningioma. TERT promoter mutations are observed in other CNS tumor types and are not seen in CNS reactive non-neoplastic processes. TERT promoter mutations are also a molecular biomarker in non-CNS tumors, including hepatocellular tumors, melanoma, myxoid liposarcoma, thyroid carcinoma and urothelial carcinoma.
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.
Cautions
A negative (wildtype) result does not rule out the presence of a mutation that may be present but below the limits of detection of this assay. The analytical sensitivity of this assay for mutation detection is 1% mutant copies in a sample with 5% or more tumor cells/cells of interest.
This test detects TERT promoter mutations in 2 hotspots (C228T and C250T) only. Other alterations within the TERT promoter are not detectable by this test.
Rare genetic alterations (ie, 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, 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 cytology slides and formalin-fixed, paraffin-embedded tissues; other types of fixatives are discouraged. Improper or other treatment of tissues, such as decalcification, may cause droplet digital polymerase chain reaction failure.
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.
Supportive Data
The TERT C228T and C250T droplet digital polymerase chain reaction (ddPCR) assays were shown to be reproducible, with 100% concordance for intra/inter-assay reproducibility experiments. Concordance between results by ddPCR and next-generation sequencing (NGS) for formalin-fixed paraffin-embedded samples was 98% (52/53), with the single discordant result (positive by ddPCR and negative for NGS) explained by the increased sensitivity of ddPCR relative to NGS technology. The analytical sensitivity of these assays was shown to be 1% fraction abundance of mutant copies at 2.5 ng DNA input (equivalent to at least 495 wild-type copies). All expected negative samples tested negative, and there was no cross reactivity between TERT C228T and C250T assays.
Method Description
Droplet digital polymerase chain reaction method is performed to test for the presence of hotspot c.-124C>T (C228T) and c.-146C>T (C250T) mutations in the promoter region of the TERT gene.(Unpublished Mayo method)
|
Gene |
GenBank Accession Number |
Chromosome (Genome build) |
|
TERT promoter |
NM_198253 |
Chromosome 5 (GRCh37/hg19) |
Day(s) Performed
Monday through Friday
Report Available
6 to 12 daysSpecimen Retention Time
FFPE tissue block: Unused portions of blocks will be returned 10 to 14 days after testing is complete; FFPE tissue/cytology slides: Unused slides are stored indefinitely and not returned; Digital images are obtained and stored for all slides used in testing.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
81345
88381-Microdissection, manual
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TERTD | TERT Promoter Analysis ddPCR, Tumor | 95778-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 618698 | Result Summary | 50397-9 |
| 618699 | Result | 82939-0 |
| 618700 | Interpretation | 69047-9 |
| 618701 | Additional Information | 48767-8 |
| 618704 | Specimen | 31208-2 |
| 618705 | Source | 31208-2 |
| 618706 | Tissue ID | 80398-1 |
| 618702 | Method | 85069-3 |
| 618703 | Disclaimer | 62364-5 |
| 618707 | Released By | 18771-6 |