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HelpTest Code CTNBT B-Catenin Mutation Analysis, 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.
Useful For
Distinguishing desmoid-type fibromatosis from other soft tissue tumors by assessing gene targets within the beta-catenin (CTNNB1) gene
Genetics Test Information
This test uses targeted next-generation sequencing to evaluate for somatic mutations within the CTNNB1 gene. See Targeted Genes and Methodology Details for B-Catenin Mutation Analysis for details regarding the targeted gene regions evaluated by this test.
This test is performed to evaluate for somatic mutations within solid tumor samples. It does not assess for germline alterations within the CTNNB1 gene.
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.
Special Instructions
Method Name
Sequence Capture and Targeted Next-Generation Sequencing (NGS)
Reporting Name
B-Catenin Mutations Analysis, 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, except for cytology slides Extracted nucleic acid (DNA/RNA) |
Reject |
Clinical Information
Desmoid-type fibromatosis is a locally invasive soft tissue tumor. The histological diagnosis of desmoid-type fibromatosis is challenging. Mutations in exon 3 of the beta-catenin (CTNNB1) gene have been identified in 50% to 87% of desmoid-type fibromatosis, including T41A (121 A>G), S45P (133 T>C), and S45F (134 C>T), but not in other soft tissue tumors. Patients harboring beta-catenin mutations may have a higher recurrence rate compared to the patients with wildtype beta-catenin.
This test uses formalin-fixed paraffin-embedded tissue or cytology slides to assess for common somatic mutations in the beta-catenin gene known to be associated with desmoid-type fibromatosis. The results of this test can be useful for supporting a diagnosis of desmoid-type fibromatosis and predicting prognosis.
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.
Day(s) Performed
Monday through Friday
Report Available
12 to 20 daysSpecimen Retention Time
FFPE tissue block: Unused portions of blocks will be returned within 10 to 14 days after testing is complete; FFPE tissue/cytology slides: Unused tissue slides are stored indefinitely; Digital images are obtained and stored for all slides used in testingPerforming 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
81479
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CTNBT | B-Catenin Mutations Analysis, Tumor | 103678-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 617921 | Result | 82939-0 |
| 617922 | Interpretation | 69047-9 |
| 617923 | Additional Information | 48767-8 |
| 617924 | Specimen | 31208-2 |
| 617925 | Tissue ID | 80398-1 |
| 617926 | Method | 85069-3 |
| 617927 | Disclaimer | 62364-5 |
| 617928 | Released By | 18771-6 |
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.