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Chronic Lymphocytic Leukemia FISH Panel by Fluorescence In Situ Hybridization (FISH) Analysis

MYB gene (6q23), ATM gene (11q22.3), D13S319 locus at 13q14.3, LAMP1 gene at 13q34, chromosome 12 alpha satellite region, chromosome 6 alpha satellite region, p53 gene (17p13.1), IGH/CCND1 t(11;14)(q13;q32)

Test Codes

EPIC: LAB6671

Department

Cytogenetics

Specimen Collection Criteria

Collect: Peripheral blood or bone marrow aspirate in a Dark Green-top Sodium Heparin tube.

A copy of the requisition must be sent with the specimen.

Physician Office/Draw Specimen Preparation

Do not freeze specimen. Maintain specimens at room temperature (20-25°C or 68-77°F) prior to courier pickup. For delays in transport (greater than 48 from the time of collection), refrigerate (2-8°C or 36-46°F) the specimen.

Preparation for Courier Transport

Transport: Peripheral blood or bone marrow, at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F).

Rejection Criteria

Specimens arriving in the laboratory 4 days or more following the original collection date.

Fixed or frozen specimens.

In-Lab Processing

Specimens are processed immediately upon receipt in the Laboratory.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 48 hours
Refrigerated (2-8°C or 36-46°F): 96 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days. A backup cell pellet is maintained for three weeks after the case has been signed out.

Laboratory

Royal Oak Cytogenetics Laboratory

Performed

Monday – Friday, 8:00 am – 5:00 pm.
Results available within 7 days of receipt in the Laboratory.

Reference Range

Positive or negative for a neoplastic clone. An interpretative report will be provided.

Test Methodology

Fluorescence In Situ Hybridization (FISH) Analysis.

Interpretation

A neoplastic clone is detected when the percent of cells with any given chromosome abnormality exceeds the threshold (normal reference range) established for each probe. Patients with a chromosome 17p (p53 gene) deletion have the poorest prognosis, followed by patients with chromosome 11q (ATM gene) deletions, those with trisomy 12, and those with a normal karyotype. The best prognosis is associated with a chromosome 13q (D13S319, LAMP1 gene) deletion.

Clinical Utility

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in North America. The identification of certain chromosome abnormalities in this disease has both diagnostic and prognostic implications. Unfortunately, the yield of cytogenetic abnormalities by conventional analysis in CLL is relatively low because of the low in vitro mitotic activity of tumor cells. Utilization of a CLL FISH panel increases this yield dramatically. In one study, the detection rate was increased from 16% (conventional analysis) to 75% (FISH). Therefore, this multiplex FISH assay is a necessary supplement to conventional cytogenetic analysis in this disease. As both a diagnostic and prognostic assay, this should be performed on new cases of CLL. The CLL FISH panel consists of four DNA probe sets that recognize the MYB gene at chromosome 6q23, chromosome 6 alpha-satellite region, ATM gene, IGH/CCND1 gene rearrangement associated with the t(11;14)(q13;q32), chromosome 12 alpha-satellite region, D13S319 locus at 13q14.3, LAMP1 gene at 13q34, and p53 gene at 17p13.1. 

Guidelines for Cytogenetic/Molecular Follow-Up Testing of Hematopoietic Malignancy

Reference

1. Zenz, et al (2011): Importance of Genetics in Chronic Lymphocytic Leukemia. Blood Reviews (25), 131-137.

CPT Codes

88271x9 (DNA probe, each), 88275x4 (Interphase analysis, 100-300 cells)

Contacts

Last Updated

12/30/2022