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Test Code ROS1F Lung Cancer, ROS1 (6q22) Rearrangement, FISH, Tissue

Useful For

Fluorescence in situ hybridization (FISH) testing for ROS1 allows for the detection of most ROS1 rearrangements, therefore, is useful for identifying tumors that may be sensitive to directed therapy

 

ROS1 FISH testing may also support the diagnosis of inflammatory myofibroblastic tumor, certain cutaneous melanocytic tumors, or other neoplasms when used in conjunction with pathologic assessment

Reflex Tests

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

Testing Algorithm

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

 

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

ROS1 (6q22), FISH, Ts

Specimen Type

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.

 

Multiple oncology (cancer) gene panels are also available. For more information see Hematology, Oncology, and Hereditary Test Selection Guide



Additional Testing Requirements


Confirmation testing for the presence of a possible ROS1 fusion transcript by next generation sequencing to resolve atypical or unbalanced fluorescence in situ hybridization results is available, order MCLNR / MayoComplete Lung Rearrangements, Rapid Test, Tumor.



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.

The following information must be included in the report provided.?

1. Patient name

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

3. Date of collection

4. 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 will be attempted but are less favorable for successful results by FISH testing; 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 4 unstained

Collection Instructions: Submit 4 consecutive unstained, positively charged, unbaked slides with 5 micron-thick sections of the tumor tissue and 1 slide stained with hematoxylin and eosin.


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

The ROS1 gene at 6q22 encodes a tyrosine kinase receptor. Chromosomal rearrangements resulting in fusion of the 3’ aspect of the ROS1 gene with the 5’ aspect of various partner genes was first identified in non-small cell carcinomas of the lung. ROS1 fusions have since been identified in various other neoplasms including but not limited to inflammatory myofibroblastic tumors and cutaneous melanocytic tumors.

 

Clinical data has shown that tumors harboring ROS1 fusions may be sensitive to directed tyrosine kinase inhibitor therapy.

Reference Values

An interpretive report will be provided.

Interpretation

A result is considered positive when the percent of cells separation of the ROS1 FISH probes exceeds the normal cutoff for the ROS1 FISH probe set.

 

A positive result is consistent with rearrangement of the ROS1 gene and likely reflects ROS1 fusion with a partner gene. The significance of this finding is dependent on the clinical and pathologic features.

 

A positive result suggests that the tumor may be responsive to directed therapy in the proper clinical and pathologic context. While results may indicate the potential response to directed tyrosine kinase inhibitors, selection of treatment remains a clinical decision.

 

A positive result may support a certain diagnosis in a particular clinical and pathologic context.

 

A negative result does not exclude the presence of a ROS1 fusion or exclude the possible sensitivity to targeted therapy.

Cautions

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

 

This fluorescence in situ hybridization (FISH) assay does not rule out other chromosome abnormalities.

 

Fixatives other than formalin (eg, Prefer, Bouin's) may not be successful for 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. The pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing if insufficient tissue/tumor is available for testing.

 

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

Day(s) Performed

Monday through Friday

Report Available

7 to 10 days

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)        

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ROS1F ROS1 (6q22), FISH, Ts 81747-8

 

Result ID Test Result Name Result LOINC Value
52235 Result Summary 50397-9
52237 Interpretation 69965-2
54595 Result 62356-1
CG755 Reason for Referral 42349-1
52238 Specimen 31208-2
52239 Source 31208-2
52240 Tissue ID 80398-1
52241 Method 85069-3
55035 Additional Information 48767-8
53821 Disclaimer 62364-5
52242 Released By 18771-6

Forms

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