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Test Code SDHMP SDH 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 Requirement for Solid Tumor Next-Generation Sequencing. In this document, the sizes are given as 4 mm 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.


Secondary ID

619712

Useful For

Identifying specific mutations within the SDHA, SDHB, SDHC, and SDHD genes to assist in tumor diagnosis/classification, including pheochromocytoma/paraganglioma, renal cell carcinoma, and pituitary adenoma

Genetics Test Information

This test uses targeted next-generation sequencing to evaluate for somatic mutations within the SDHA, SDHB, SDHC, and SDHD genes. See Targeted Genes and Methodology Details for SDH Genes 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. 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

SDH Genes Mutation Analysis, Tumor

Specimen Type

Varies

Specimen 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

Disease-causing alterations of the succinate dehydrogenase complex genes (including SDHA, SDHB, SDHC, and SDHD) have been implicated in multiple tumor types, including pheochromocytoma/paraganglioma, renal cell carcinoma, gastrointestinal stromal tumors, and pituitary adenoma. Germline alterations of the SDH genes have been associated with hereditary pheochromocytoma/paraganglioma syndromes. The 5th edition of the World Health Organization classification of tumors recognizes succinate dehydrogenase-deficient renal cell carcinoma as a molecularly defined entity.(1) This assay, performed using formalin-fixed paraffin-embedded tissue or cytology material, is therefore helpful in documenting an underlying pathogenic alteration of the SDH genes and is diagnostically significant. Note that this assay does not distinguish between germline and somatic alterations or identify epigenetic alterations of interest (such as SDHC promoter hypermethylation).

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

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 result does not rule out the presence of a variant that may be present below the limits of detection of this assay. In a specimen with 20% or more tumor content, the analytical sensitivity of this assay for sequence reportable alterations is 5% mutant allele frequency with a minimum coverage of 500X.

 

Point mutations and small deletion-insertion mutations will be detected in the SDHA, SDHB, SDHC, and SDHD genes only. This test may detect single exon deletions but does not detect multi-exon deletions, duplications, epigenetic alterations (such as promoter hypermethylation), or genomic copy number variants.

 

Variant allele frequency (VAF) is the percentage of sequencing reads supporting a specific variant divided by the total sequencing reads at that position. In somatic testing, VAF should be interpreted in the context of several factors, including, but not limited to, tumor purity/heterogeneity/copy number status (ploidy, gains/losses, loss of heterozygosity) and sequencing artifact/misalignment.(2,3)

 

Rare 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, tumor sampling, histopathological, and other laboratory data. If results obtained do not match other clinical or laboratory findings, contact the laboratory for discussion. 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 treatment of tissues, such as decalcification, may cause polymerase chain reaction failure.

Supportive Data

Performance Characteristics:

The limit of detection for calling a somatic variant (single nucleotide variants [SNV] and deletions-insertions [delins, formerly indel]) is 5% variant allele frequency (VAF) and having at least 500x deduplicated coverage.

 

Verification studies demonstrated concordance between this test and the reference method for detection of SNV and delins is 98.5% (673/683) and 98.4% (122/124) of variants, respectively. Concordance for the detection of delins was 99.0% (100/101) in variants 1 to 10 base pairs (bp) in size, 93.3% (14/15) in variants 11 to 50 bp in size, and 100% (8/8) in variants over 50 bp in size.

 

To ensure accuracy, this test will be performed on cases that are estimated by a pathologist to have at least 20% tumor cells.

Clinical Reference

1. WHO Classification of Tumours Editorial Board, eds. Urinary and male genital tumors. 5th ed. World Health Organization; 2022. WHO Classification of Tumours. Vol 8

2. 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

3. 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

4. Trpkov K, Hes O, Williamson SR, et al. New developments in existing WHO entities and evolving molecular concepts: The Genitourinary Pathology Society (GUPS) update on renal neoplasia. Mod Pathol. 2021;34(7):1392-1424

5. Fuchs TL, Maclean F, Turchini J, et al. Expanding the clinicopathological spectrum of succinate dehydrogenase-deficient renal cell carcinoma with a focus on variant morphologies: a study of 62 new tumors in 59 patients. Mod Pathol. 2022;35(6):836-849

6. Gupta S, Swanson AA, Chen YB, et al. Incidence of succinate dehydrogenase and fumarate hydratase-deficient renal cell carcinoma based on immunohistochemical screening with SDHA/SDHB and FH/2SC. Hum Pathol. 2019;91:114-122

7. Carlo MI, Hakimi AA, Stewart GD, et al. Familial kidney cancer: Implications of new syndromes and molecular insights. Eur Urol. 2019;76(6):754-764

8. Gupta S, Erickson LA. Back to biochemistry: Evaluation for and prognostic significance of SDH mutations in paragangliomas and pheochromocytomas. Surg Pathol Clin. 2023;16(1):119-129

Method Description

Next-generation sequencing is performed to evaluate the presence of a mutation in most coding regions of the SDHA, SDHB, SDHC, and SDHD genes. See Targeted Genes and Methodology Details for SDH Genes Mutation Analysis for details regarding the targeted gene regions identified by this test.(Unpublished Mayo method)

 

A pathology review and macro dissection to enrich for tumor cells is performed prior to slide scraping.

Day(s) Performed

Monday through Friday

Report Available

12 to 20 days

Specimen 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; 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

88381-Microdissection, manual

81404

81405 x2

81406

81479 (if appropriate for government payers)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SDHMP SDH Genes Mutation Analysis, Tumor 105598-7

 

Result ID Test Result Name Result LOINC Value
619713 Result 82939-0
619714 Interpretation 69047-9
619715 Additional Information 48767-8
619716 Specimen 31208-2
619717 Tissue ID 80398-1
619718 Method 85069-3
619719 Disclaimer 62364-5
619720 Released By 18771-6

Forms

If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.