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Test Code PRKAF Fibrolamellar Carcinoma, 19p13.1 (PRKACA) Rearrangement, FISH, Tissue

Useful For

Aid in the diagnosis of identifying PRKACA gene rearrangements of patients with fibrolamellar carcinoma

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

Testing Algorithm

This test does not include a pathology consultation. If a pathology consultation is requested, PATHC / Pathology Consultation should be ordered, and the appropriate fluorescence in situ hybridization test will be performed at an additional charge.

 

Appropriate ancillary probes may be performed at consultant discretion to render comprehensive assessment. Any additional probes will have the results included within the final report and will be performed at an additional charge.

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

PRKACA, Rearrangement, FISH, Ts

Specimen Type

Tissue


Necessary Information


1. A pathology report is required in order for testing to be performed. Acceptable pathology reports include working drafts, preliminary pathology or surgical pathology reports.

2. 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:

 

Specimen Type: Tissue

Container/Tube: Formalin-fixed, paraffin-embedded tumor tissue block

 

Specimen Type: Slides

Slides/Slide Count: Three consecutive, unstained, 5 micron-thick sections placed on positively charged slides, and 1 hematoxylin and eosin-stained slide


Specimen Minimum Volume

Two consecutive, unstained, 5 micron-thick sections placed on positively charged slides, and 1 hematoxylin and eosin-stained slide.

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

DNAJB1-PRKACA fusion has been associated with a distinct subtype of hepatocellular carcinoma called fibrolamellar carcinoma. A break-apart strategy FISH probe has been developed to detect the rearrangement event that occurs in the DNAJB1-PRKACA fusion, specifically the loss of the 5' region labeled in red and retention of the 3' region labeled in green.

Reference Values

An interpretive report will be provided.

Interpretation

A positive result with the PRKACA probe is detected when the percent of cells with an abnormality exceeds the normal cutoff for the probe set.

 

A positive result of PRKACA suggests fusion of the PRKACA and DNAJB1 genes at 19p13.1. A negative result suggests no fusion of the PRKACA and DNAJB1 genes has occurred.

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) may not be successful for FISH assays, however non-formalin fixed samples will not be rejected.


Paraffin-embedded tissues that have been decalcified are generally unsuccessful for FISH analysis. The pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing.

Supportive Data

FISH analysis was performed on 60 formalin-fixed paraffin-embedded specimens including 10 fibrolamellar carcinoma tissue samples, 25 non-fibrolamellar carcinoma liver tumor samples, and 25 noncancerous control specimens. The normal controls were used to generate the normal cutoff values. Structural alterations resulting in the rearrangement of the PRKACA gene region were identified and results correlated with pathology and previous FISH findings.

Method Description

This test uses a laboratory developed PRKACA (19p13.1) dual-color break-apart probe (BAP) strategy. 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 etcher on the back of the unstained slide to be assayed. The probes are hybridized to the appropriate target areas and 2 technologists analyze each probe set. Using the PRKACA probe set, each technologist analyzes 50 interphase nuclei (100 total) and the results are 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 to CAP and NYS requirements. Client provided paraffin blocks and extra unstained slides (if provided) 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)

88271x1-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
PRKAF PRKACA, Rearrangement, FISH, Ts 104670-5

 

Result ID Test Result Name Result LOINC Value
40669 Result Summary 50397-9
40670 Interpretation 69965-2
40671 Result 62356-1
40672 Reason for Referral 42349-1
40673 Specimen 31208-2
40674 Source 31208-2
40675 Tissue ID 80398-1
40676 Method 85069-3
40677 Additional Information 48767-8
40678 Disclaimer 62364-5
40679 Released By 18771-6

Forms

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