FISH, HER-2/neu with Reflex to IHC

Test Code

19859

CPT Codes
88377

Includes

If HER-2 is equivocal, then HER-2, IHC with Interpretation will be performed at an additional charge (CPT code(s): 88360).

Preferred Specimen

Formalin-fixed paraffin-embedded tissue block

Other Acceptable Specimens

4-5 microns sections on charged slides (x6)

Instructions

Invasive primary or metastatic breast or gastric cancer formalin-fixed, paraffin-embedded tissue or charged/+slides from formalin-fixed, paraffin-embedded tissue. Specimen MUST be fixed in 10% neutral buffered formalin. Cold ischemic time of less than 1 hour and fixation between 6 and 72 hours is recommended.

Pathology report must accompany paraffin block or slides.

Information required in this report includes: Physician identification, specimen identifiers (case and block number), specimen site and type, collection date, collection time, tissue processing used (routine or microwave), cold ischemic time, type of fixative, duration of fixation, pathologic diagnosis, and IHC score, if performed elsewhere. Ship at room temperature. Do not freeze. Do not reject.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: See Collection Instructions
Refrigerated: See Collection Instructions
Frozen: See Collection Instructions

Methodology
Fluorescence in situ Hybridization (FISH)

FDA Status

The analytical performance characteristics of this assay have been determined by Quest Diagnostics. The modifications have not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Daily; Report available: 4-5 days

Reference Range

See Laboratory Report

Clinical Significance

This test uses fluorescence in situ hybridization (FISH) to detect HER2 (also known as ERBB2 or HER-2/neu) oncogene amplification in the invasive component of a breast cancer specimen. This test may be used in patients with diagnosed breast cancer to assess eligibility for HER2-targeted therapy [1,2]. An inconclusive pattern of the results will reflex to an immunohistochemistry (IHC) test on the same specimen.

The HER2 gene (also known as ERBB2 or HER-2/neu) encodes the human epidermal growth factor receptor 2. HER2 gene amplification and/or HER2 overexpression are found in up to 20% of primary breast cancers and are associated with adverse disease outcomes [1,3]. HER2 status is most often used to determine patient eligibility for HER2-targeted therapies. These HER2-targeted therapies are not recommended for breast cancers lacking amplification/overexpression of HER2 [1]. Therefore, detection of HER2 amplification/overexpression is important for identifying patients whose cancers are likely to respond to this type of targeted treatment.

The American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) Expert Panel recommends HER2 testing of the invasive component of primary or metastatic tumor tissue in all patients with newly diagnosed breast cancer [2].

HER2 status can be assessed by detecting either protein overexpression with immunohistochemistry (IHC) or gene amplification with FISH. If the initial FISH test yields an inconclusive result, then reflex testing using IHC will be performed [2].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Wolff AC, et al. Arch Pathol Lab Med. 2014;138(2):241-256.
2. Wolff AC, et al. Arch Pathol Lab Med. 2018;142(11):1364-1382.
3. Ross JS, et al. Stem Cells. 1998;16(6):413-428.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.