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Test Code TGOGF TGFBR3 (1p22), OGA (10q24) Rearrangement, FISH, Tissue


Ordering Guidance


This test does not include a pathology consultation. If a pathology consultation is requested, order PATHC / Pathology Consultation, and appropriate testing will be added at the discretion of the pathologist and performed at an additional charge.



Shipping Instructions


Advise Express Mail or equivalent if not on courier service.



Necessary Information


1. A pathology report is required for testing to be performed. If not provided, appropriate testing and/or interpretation may be compromised or delayed. Acceptable pathology reports include working drafts, preliminary pathology, or surgical pathology reports.

2. The following information must be included in the report provided:

-Patient name

-Block number - must be on all blocks, slides, and paperwork

-Date of collection

-Tissue source

3. A reason for testing must be provided. If this information is not provided, an appropriate indication for testing may be entered by Mayo Clinic Laboratories.



Specimen Required


Submit only 1 of the following specimens:

Preferred

Specimen Type: Tissue block

Collection Instructions: Submit a formalin-fixed, paraffin-embedded tumor tissue block. Blocks prepared with alternative fixation methods may be acceptable; provide fixation method used.

Additional Information:

1. Paraffin-embedded specimens can be from any anatomic location (skin, soft tissue, lymph node, etc).

2. Bone specimens that have been decalcified will be attempted for testing, but the success rate is approximately 50%.

Acceptable

Specimen Type: Tissue slides

Slides: 1 Hematoxylin and eosin stained and 6 unstained

Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 6 consecutive unstained, positively charged, unbaked slides with 5 micron-thick sections of the tumor tissue.


Useful For

Supporting the diagnosis of pleomorphic hyalinizing angiectatic tumor, or hemosiderotic fibrolipomatous tumors associated with rearrangement of the OGA and/or TGFBR3 gene when used in conjunction with an anatomic pathology consultation

Testing Algorithm

This test includes a charge for the probe application, analysis, and professional interpretation of results for 2 probe sets (4 individual fluorescence in situ hybridization [FISH] probes). No analysis charges will be incurred if an insufficient number of representative cells are available for analysis.

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

TGFBR3, OGA, FISH, Ts

Specimen Type

Tissue

Specimen Minimum Volume

Slides: 1 Hematoxylin and eosin stained and 2 unstained

Specimen Stability Information

Specimen Type Temperature Time Special Container
Tissue Ambient (preferred)
  Refrigerated 

Reject Due To

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

Clinical Information

Chromosomal rearrangement involving the OGA (previously MGEA5) gene or the TGFBR3 gene have recently been associated with both pleomorphic hyalinizing angiectatic tumor of soft parts and hemosiderotic fibrolipomatous tumor. Either one or both rearrangements may be present and support a diagnosis in the proper clinical and pathologic context. Rearrangement of one or both genes may be present in other neoplastic processes and is not diagnostic in isolation. These rearrangements are unusual in that they do not result specific RNA transcript products and therefore are often not detectable through many next-generation sequencing approaches but can typically be detected by fluorescence in situ hybridization testing.

Reference Values

An interpretive report will be provided.

Interpretation

The result is considered positive when the percent of cells with separation of the OGA and/or TGFBR3 FISH probes with an abnormality exceeds the normal cutoff for the OGA and/or TGFBR3 FISH probe set.

 

A positive result suggests rearrangement of the OGA and/or TGFBR3 gene and likely reflects OGA and/or TGFBR3 fusion with a partner gene. The significance of this finding is dependent on the clinical and pathologic features.

 

The result is considered negative when the percent of cells with separation of the OGA and/or TGFBR3 FISH probes does not exceed the normal cutoff for the OGA or TGFBR3 FISH probe set.

 

A negative result does not exclude the presence of a OGA or TGFBR3 rearrangement.

 

Rearrangement of the OGA or TGFBR3 gene may be present in other neoplastic processes.

Cautions

This test is not approved by the US Food and Drug Administration, and it is best used as an adjunct to existing clinical and pathologic information.

 

Fixatives other than formalin (eg, Prefer, Bouin's) may not be successful for fluorescence in situ hybridization (FISH) assays. Non-formalin fixed specimens will not be rejected.

 

Paraffin-embedded tissues that have been decalcified may not be successful for FISH analysis. The success rate of FISH studies on decalcified tissue is approximately 50%.

 

FISH studies will be attempted if sufficient tumor is present for analysis. If insufficient tissue/tumor is available for testing, the pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing.

 

If no FISH signals are observed post-hybridization, the case will be released indicating a lack of FISH results.

Method Description

The test is performed using laboratory-developed TGFBR3 (1p22) and OGA (10q24) dual-color break-apart strategy probes. Formalin-fixed, paraffin-embedded tissues are cut at 5 microns and mounted on positively charged glass slides. The selection of tissue and the identification of target areas on the hematoxylin and eosin (H and E)-stained slide are performed by a pathologist. Using the H and E-stained slide as a reference, target areas are etched with a diamond-tipped engraving tool on the back of the unstained slide to be assayed. The probe set is hybridized to the appropriate target areas, and 2 technologists independently analyze 50 interphase nuclei (100 total) with the results expressed as the percent of abnormal nuclei.(Unpublished Mayo method).

Day(s) Performed

Monday through Friday

Report Available

7 to 10 days

Specimen Retention Time

Slides and H&E used for analysis are retained by the laboratory in accordance with regulatory requirements. Client provided paraffin blocks and extra unstained slides will be returned after testing is complete.

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

88271x2, 88291 DNA probe, each (first probe set), Interpretation and report

88271x2-DNA probe, each; each additional probe set (if appropriate)

88271-DNA probe, each; coverage for sets containing 3 probes (if appropriate)

88271x2-DNA probe, each; coverage for sets containing 4 probes (if appropriate)

88271x3-DNA probe, each; coverage for sets containing 5 probes (if appropriate)

88274 w/modifier 52-Interphase in situ hybridization, <25 cells, each probe set (if appropriate)

88274-Interphase in situ hybridization, 25 to 99 cells, each probe set (if appropriate)

88275-Interphase in situ hybridization, 100 to 300 cells, each probe set (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TGOGF TGFBR3, OGA, FISH, Ts In Process

 

Result ID Test Result Name Result LOINC Value
621842 Result Summary 50397-9
621843 Interpretation 69965-2
621844 Result 62356-1
GC145 Reason for Referral 42349-1
621845 Specimen 31208-2
621846 Source 31208-2
621847 Tissue ID 80398-1
621848 Method 85069-3
621849 Additional Information 48767-8
621850 Disclaimer 62364-5
621851 Released By 19139-5

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
_PBCT Probe, +2 No No
_PADD Probe, +1 No No
_PB02 Probe, +2 No No
_PB03 Probe, +3 No No
_IL25 Interphases, <25 No No
_I099 Interphases, 25-99 No No
_I300 Interphases, >=100 No No