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

Useful For

Identifying c-ros oncogene 1 (ROS1) gene rearrangements in patients with late-stage, lung adenocarcinomas that are negative for epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements

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


This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results.


Additional charges will be incurred for all reflex probes performed. Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred.

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

ROS1 (6q22), FISH, Ts

Specimen Type


Shipping Instructions

Advise Express Mail or equivalent if not on courier service.

Necessary Information

Provide a reason for referral and pathology report with each specimen. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed.

Specimen Required

Submit only 1 of the following specimens:


Specimen Type: Tissue

Preferred: Tissue block

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


Acceptable: Slides

Slides: Four 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
Tissue Ambient (preferred)

Clinical Information

Lung cancer is the leading cause of cancer mortality in developed countries. The discovery of a variety of genetic alterations in non-small-cell lung cancer (NSCLC) has enabled the use of targeted therapy such as the anaplastic lymphoma kinase (ALK) inhibitor, crizotinib, and the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, erlotinib, for NSCLC with ALK rearrangements and EGFR mutations, respectively.


The c-ros oncogene 1 (ROS1), originally described in glioblastomas, has been identified as a potential relevant therapeutic target in lung adenocarcinoma. Crizotinib has shown in vitro activity and early evidence of clinical activity in ROS1-rearranged tumors.

Reference Values

An interpretive report will be provided.


A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal cutoff for the probe set.


A positive result suggests rearrangement of the ROS1 locus and a tumor that may be responsive to ALK-inhibitor therapy.


A positive result suggests rearrangement of the c-ros oncogene 1 (ROS1) locus and a tumor that may be responsive to anaplastic lymphoma kinase (ALK)-inhibitor therapy

Clinical Reference

1. Suehara Y, Arcila M, Wang L, et al: Identification of KIF5B-RET and GOPC-ROS1 fusions in lung adenocarcinomas through a comprehensive mRNA-based screen for tyrosine kinase fusions. Clin Cancer Res 2012;18(24):6599-6608

2. Takeuchi K, Soda M, Togashi Y, et al: RET, ROS1 and ALK fusions in lung cancer. Nat Med 2012;18(3):378-381

3. Bergethon K, Shaw AT, Ou SH, et al: ROS1 rearrangements define a unique molecular class of lung cancers. J Clin Oncol 2012;30(8):863-870

4. Chin LP, Soo RA, Soong R, Ou SH: Targeting ROS1 with anaplastic lymphoma kinase inhibitors: a promising therapeutic strategy for a newly defined molecular subset of non-small-cell lung cancer. J Thorac Oncol 2012;7(11):1625-1630

Day(s) and Time(s) Performed

Samples processed Monday through Sunday. Results reported Monday through Friday, 8 a.m.-5 p.m.

Analytic Time

7 days

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. 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
ROS1F ROS1 (6q22), FISH, Ts In Process


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 49549-9
55035 Additional Information 48767-8
53821 Disclaimer 62364-5
52242 Released By 18771-6
Mayo Clinic Laboratories | Oncology Catalog Additional Information: