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Test Code THYRP Hereditary Thyroid Cancer Panel, Varies


Ordering Guidance


Customization of this panel and single gene analysis for any gene present on this panel are available. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.

 

Targeted testing for familial variants (also called site-specific or known mutations testing) is available for the genes on this panel. For more information see FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. For instructions for testing patients who have received a bone marrow transplant, call 800-533-1710.

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Green top (Sodium heparin)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

Specimen Stability Information: Ambient 4 days/Refrigerated 4 days/Frozen 4 days

Additional Information:

1. Specimens are preferred to be received within 4 days of collection. Extraction will be attempted for samples received after 4 days, and DNA yield will be evaluated to determine if testing may proceed.

2. To ensure minimum volume and concentration of DNA is met, the preferred volume of blood must be submitted. Testing may be canceled if DNA requirements are inadequate.

 

Specimen Type: Saliva

Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.

Supplies: Saliva Swab Collection Kit (T786)

Specimen Volume: 1 Swab

Collection Instructions: Collect and send specimen per kit instructions.

Specimen Stability Information: Ambient (preferred) 30 days/Refrigerated 30 days

Additional information: Due to lower quantity/quality of DNA yielded from saliva, some aspects of the test may not perform as well as DNA extracted from a whole blood sample. When applicable, specific gene regions that were unable to be interrogated will be noted in the report. Alternatively, additional specimen may be required to complete testing.


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519)

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

Secondary ID

614580

Useful For

Evaluating patients with a personal or family history suggestive of a hereditary thyroid cancer syndrome

 

Establishing a diagnosis of a hereditary thyroid cancer syndrome, allowing for targeted surveillance based on associated risks

 

Identifying genetic variants associated with increased risk for thyroid and other cancers, allowing for predictive testing and appropriate screening of at-risk family members

Method Name

Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing

Reporting Name

Hereditary Thyroid Cancer Panel

Specimen Type

Varies

Specimen Minimum Volume

Whole blood: 1 mL; Saliva: See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time
Varies Varies

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

The lifetime risk to develop thyroid cancer is approximately 1.2%.(1) Rarely, a predisposition to thyroid cancer may be inherited in families with certain genetic alterations. Most of these genetic alterations are syndromic, meaning individuals who inherit them are usually at risk for other types of cancers or features, in addition to thyroid cancer.

 

Papillary thyroid cancers are typically sporadic but can be seen in individuals or families with familial adenomatous polyposis (FAP) syndrome, caused by variants within the APC gene (cribriform morular variant). Individuals with FAP are at also very high risk for colonic polyposis and colorectal cancer.

 

Follicular or papillary thyroid cancers may be seen in families with PTEN hamartoma tumor syndrome (PHTS). Individuals with disease-causing PTEN variants have a 70-fold increased incidence of thyroid cancer compared to the general population and are at increased risk to develop breast and endometrial cancer.(2)

 

Thyroid cancers with follicular or papillary features can also be seen in individuals with disease-causing DICER1 variants, as well as individuals with Carney complex, which is caused by disease-causing variants within the PRKAR1A gene.(3,4)

 

Approximately 25% of cases of medullary thyroid cancer (MTC) are caused by an inherited RET variant.(5) Some disease-causing RET variants are associated with only isolated, familial MTC, while others cause a syndrome called multiple endocrine neoplasia type 2 (MEN2). Individuals with MEN2 have a high risk for MTC and may also have other tumors of the endocrine/neuroendocrine system, including paragangliomas, mucosal neuromas, pheochromocytomas, and parathyroid tumors.(6)

 

The National Comprehensive Cancer Network and the American Cancer Society provide recommendations regarding the medical management of individuals with hereditary thyroid cancer syndromes.(7)

Reference Values

An interpretive report will be provided.

Interpretation

All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(8) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Method Description

Next-generation sequencing (NGS) and/or Sanger sequencing are performed to test for the presence of variants in coding regions and intron/exon boundaries of the genes analyzed, as well as some other regions that have known disease-causing variants. The human genome reference GRCh37/hg19 build was used for sequence read alignment. At least 99% of the bases are covered at a read depth over 30X. Sensitivity is estimated at above 99% for single nucleotide variants, above 94% for deletions-insertions (delins) less than 40 base pairs (bp), above 95% for deletions up to 75 bp and insertions up to 47 bp. NGS and/or a polymerase chain reaction-based quantitative method is performed to test for the presence of deletions and duplications in the genes analyzed.

 

There may be regions of genes that cannot be effectively evaluated by sequencing or deletion and duplication analysis as a result of technical limitations of the assay, including regions of homology, high guanine-cytosine (GC) content, and repetitive sequences. For details regarding the targeted genes analyzed and specific gene regions not routinely covered see Targeted Genes and Methodology Details for Hereditary Thyroid Cancer Panel.(Unpublished Mayo method)

 

Confirmation of select reportable variants may be performed by alternate methodologies based on internal laboratory criteria.

 

Genes analyzed: APC (including promoters 1A and 1B), DICER1, PRKAR1A, PTEN (including promoter), RET, TP53, and WRN

Day(s) Performed

Varies

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

81437

LOINC Code Information

Test ID Test Order Name Order LOINC Value
THYRP Hereditary Thyroid Cancer Panel 106780-0

 

Result ID Test Result Name Result LOINC Value
614863 Test Description 62364-5
614864 Specimen 31208-2
614865 Source 31208-2
614866 Result Summary 50397-9
614867 Result 82939-0
614868 Interpretation 69047-9
614869 Resources 99622-3
614870 Additional Information 48767-8
614871 Method 85069-3
614872 Genes Analyzed 48018-6
614873 Disclaimer 62364-5
614874 Released By 18771-6