ALK (2p23) Rearrangement, FISH, Tissue (LCAF)

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Marshfield Clinic Public WebSite

Test Code: ALKRESO

Overview
Ordering
Specimen
Performing
Clinical/Interpretive
Contacts
Coding

Synonyms/Keywords

Lung carcinoma, Non-small cell lung cancer (NSCLC)

Useful For

Identifying patients with late-stage, non-small cell lung cancers who may benefit from treatment with the drug Xalkori.

This test is always reflexed when EGFR is initially ordered.

Specimen Requirements

Specimen Type	Preferred Container/Tube	Acceptable Container/Tube	Specimen Volume	Specimen Minimum Volume (allows for 1 repeat)	Pediatric Minimum Volume (no repeat)
Tissue	FFPE tumor tissue block	Slides	4 consecutive, unstained, 5 micron thick sections placed on positively charged slides and 1 H&E slide	3 consecutive, unstained, 5 micron thick sections placed on positively charged slides and 1 H&E slide

Collection Processing Instructions

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.

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.

Submit tissue block or slides.

For blocks residing at a Non-Clinic location, please complete the Surgical Pathology Specimen Request form found in FORMS PRINTER or found here:

Surgical Pathology Specimen Request

Specimen Stability Information

Specimen Type	Temperature
Tissue	Ambient (preferred)
Tissue	Refrigerated

Rejection Criteria

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

Interference

This test is intended to be used for therapeutic purposes in pulmonary carcinoma. This FISH assay does not rule out other chromosome abnormalities.

While results may indicate the likely response to ALK inhibitor therapy, selection of treatment remains a clinical decision.

Performing Laboratory Information

Performing Location	Day(s) Test Performed	Report Available	Methodology/Instrumentation
Mayo Clinic Laboratories	Monday through Friday	7 to 9 days	Fluorescence In Situ Hybridization (FISH)

Reference Lab

Mayo Clinic Laboratories

Reference Range Information

An interpretative report will be provided.

Interpretation

A positive result (ALK rearrangement identified) is detected when the percent of cells with an abnormality exceeds the normal cutoff for the ALK probe set.

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

A negative result suggests no rearrangement of the ALK gene region at 2p23.

A specimen is considered positive if >50% demonstrate a signal pattern consistent with an ALK rearrangement and considered negative if <10% of cells are positive. If the results are equivocal (>10% and <50%), an additional 50 cells are scored and would be considered positive if >15% of cells exhibit a signal pattern consistent with an ALK rearrangement and negative if <15% of cells exhibit an ALK rearrangement.

Outreach CPTs

CPT	Quantity	Description	Comments
88291	1	Interpretation and report
88271	2	Probe Set, 1ST
88271	2	Probe, +2	as needed
88271	1	Probe, +1	as needed
88271	2	Probe, +2	as needed
88271	3	Probe, +3	as needed
88274	1	Interphases, <25	as needed
88274	1	Interphases, 25-99	as needed
88275	1	Interphases, >100	as needed