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HelpTest ID: HISGT Histone Genes 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 Requirements for Solid Tumor Next-Generation Sequencing. In this document, the sizes are given as 4mm x 4mm 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 slide
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 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.
Useful For
Identifying specific mutations within the H3-3A, H3-3B, H3C2, H3C3 and H3C14 genes that assist in tumor diagnosis/classification
Genetics Test Information
This test uses targeted next-generation sequencing to evaluate for somatic mutations within the H3-3A (previously H3F3A), H3-3B (previously H3F3B), H3C2 (previously HIST1H3B), H3C3 (previously HIST1H3C), and H3C14 (previously HIST2H3C) genes. See Targeted Genes and Methodology Details for Histone Genes, Mutation Analysis for details regarding the targeted gene regions evaluated by this test.
Note: This test is performed to evaluate for somatic mutations within solid tumor samples. This test does not assess for germline alterations within the genes listed.
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.
Method Name
Sequence Capture Next-Generation Sequencing (NGS)
Reporting Name
Histone Genes Mutation Analysis, TsSpecimen Type
VariesSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Refrigerated | |||
Clinical Information
H3-3A (previously known as H3F3A) and H3-3B (previously known as H3F3B) genes encode H3.3 replication-independent histone proteins. H3C2 (previously known as HIST1H3B) and H3C3 (previously known as HIST1H3C) encode H3.1 replication-dependent histone proteins. H3C14 (previously known as HIST2H3C) encodes H3.2 replication-dependent histone protein. Mutations in H3-3A and H3-3B genes primarily involve codons K28 (also known as K27) and G35 (also known as G34), whereas mutations in H3C2, H3C3 and H3C14 involve codon K28 (also known as K27). In central nervous system tumors, H3-3A, H3C2, H3C3 and H3C14 mutations are a diagnostic molecular biomarker for diffuse midline glioma, H3 K27-altered and diffuse hemispheric glioma, H3 G34-mutant. Among bone/soft tissue tumors, H3-3A mutations are a hallmark of giant cell tumour of bone and mutations in H3-3B and H3-3A genes are typical of chondroblastoma.
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.
Clinical Reference
1. Strom SP. Current practices and guidelines for clinical next-generation sequencing oncology testing. Cancer Biol Med. 2016;13(1):3-11. doi:10.28092/j.issn.2095-3941.2016.0004
2. Spurr L, Li M, Alomran N, et al. Systematic pan-cancer analysis of somatic allele frequency. Sci Rep. 2018;8(1):7735. Published 2018 May 16. doi:10.1038/s41598-018-25462-0
3. Horbinski C, Nabors LB, Portnow J, et al. NCCN Guidelines Insights: Central Nervous System Cancers, Version 2.2022. J Natl Compr Canc Netw. 2023;21(1):12-20
4. WHO Classification of Tumours Editorial Board. Central nervous system tumours. 5th ed. World Health Organization; 2022. WHO Classification of Tumours. Vol 6
5. Sturm D, Witt H, Hovestadt V, et al: Hotspot mutations in H3F3A and IDH1 define distinct epigenetic and biological subgroups of glioblastoma. Cancer Cell. 2012 Oct 16;22(4):425-437
6. Wu G, Broniscer A, McEachron TA, et al. Somatic histone H3 alterations in pediatric diffuse intrinsic pontine gliomas and non-brainstem glioblastomas. Nat Genet. 2012 Jan:44(3):251-253
7. Schwartzentruber J, Korshunov A, Liu XY, et al: Driver mutations in histone H3.3 and chromatin remodelling genes in paediatric glioblastoma. Nature. 2012 Jan 29;482(7384):226-231
8. Behjati S, Tarpey PS, Presneau N, et al: Distinct H3F3A and H3F3B driver mutations define chondroblastoma and giant cell tumor of bone. Nat Genet. 2013 Dec;45(12):1479-82
Day(s) Performed
Monday through Friday
Report Available
12 to 20 daysTest 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
81445
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HISGT | Histone Genes Mutation Analysis, Ts | 104062-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 619587 | Result | 82939-0 |
| 619588 | Interpretation | 69047-9 |
| 619589 | Additional Information | 48767-8 |
| 619590 | Specimen | 31208-2 |
| 619591 | Tissue ID | 80398-1 |
| 619592 | Method | 85069-3 |
| 619593 | Disclaimer | 62364-5 |
| 619594 | Released By | 18771-6 |
Forms
If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.
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