Test Overview
Fluorescence In Situ Hybridization (FISH)
This test is designed to detect copy number abnormalities at probed loci via fluorescence in situ hybridization (FISH) in FFPE tissue specimens. The test is used to aid in the diagnosis of histologically ambiguous melanocytic lesions; a positive result favors a diagnosis of melanoma while a negative result one of nevus. Published data report a sensitivity of 86-100% and a specificity of 76-98% for the diagnosis of melanoma in selected cohorts including atypical spitzoid neoplasms. Three multiprobe FISH panels are available. Panel 1 include probes 6p25 (RREB1), 6q23 (MYB), 11q13 (CCND1) and CEP6; panel 2 include 9q21 (CDKN2A) and CEP9; panel 3 include 8q24 (MYC). Panel 1 is recommended for all histologically ambiguous melanocytic tumors. The addition of panels 2 and 3 increases assay sensitivity for selected melanocytic neoplasms including spitzoid tumors and nevoid melanomas. A positive result is defined as percent of nuclei with abnormal signal counts exceeding cut-off criteria for any of the probes. Results from this test should not be used alone in diagnosing a melanocytic lesion and correlation with clinical history, histological examination and other standard diagnostic procedures is necessary for diagnosis.
Interpretive report provided.
* Reference ranges may change over time. Please refer to the original patient report when evaluating results.
This test detects copy number aberrations on specific chromosomal targets (6p25, 6q23, 11q13, 9p21, and 8q24), which are documented to have frequent association with melanoma; however, it will not identify potentially significant aberrations in non-targeted chromosomal segments. A false positive result can occur in the setting of tetraploidy.
Test Details
10-14 days
- FISH for 8q24 (MYC)
- FISH panel 9q21 (CDKN2A) and CEP9
- FISH panel 6p25 (RREB1), 6q23 (MYB), 11q13 (CCND1) and CEP6
- Multiplex FISH for Melanoma
Specimen Requirements
Submit a formalin-fixed, paraffin-embedded (FFPE) block containing tumor tissue (preferred specimen). If a block is not available submit 3 FFPE unstained sections at 4-micron thickness placed on electrostatic-coated slides, unbaked and one regular H&E obtained as serial sections; store at room temperature.
Additional Information
By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.