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Adult B-Cell Acute Lymphoblastic Leukemia FISH Panel by Fluorescence In Situ Hybridization Analysis

FISH, ALL, B-cell leukemia, GPAL2
B-ALL Panel:  ETV6/RUNX1and BCR/ABL1 fusion, MLL gene rearrangement, chromosome 4, 10 trisomies, TCF3/PBX1 gene rearrangement, PDGFRB gene rearrangement, ABL1 and ABL2 gene rearrangements, and IGH/IL-3 gene rearrangement according to the Children's Oncology Group protocols

Test Codes

EPIC: LAB5203

Department

Cytogenetics

Specimen Collection Criteria

Collect: Bone marrow aspirate in a Dark Green-top Sodium Heparin tube. (Minimum: 1.0 mL)

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: 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

High hyperdiploidy defines a distinct subset characterized by a favorable prognosis. More specifically, hyperdiploid ALL with simultaneous trisomy of chromosomes 4 and 10 have the lowest treatment failure and the best clinical outcome, although such trisomy is uncommon in adult ALL compared with pediatric ALL. While the t(12;21)(p13;q22) is common in pediatric ALL, it is uncommonly observed in adult ALL. The t(12;21) is associated with a good prognosis. The Ph chromosome, t(9;22)(q34;q11.2) with BCR/ABL1 fusion has been associated with a poor prognosis in both adults and children, although treatment with tyrosine kinase inhibitors have shown benefit.  Translocations of 11q23, causing rearrangements of the MLL gene, predict a clinically aggressive disease with a poor prognosis. Another recurrent translocation in ALL, the t(1;19)(q23;p13.3), is seen in approximately 5% of adult and childhood ALL and encodes the fusion protein E2A/PBX1 (TCF3/PBX1). This was previously thought to represent a poor prognostic marker, but intensification of therapy in pediatric patients has overcome its effects on outcome. ABL1 and ABL2 rearrangement probes are utilized to detect Ph-like ABL class alterations which can inform use of tyrosine kinase inhibitors.  In addition, PDGFRB gene rearrangement results in a kinase fusion characterized as Ph-like ALL. The IGH/IL3 rearrangement observed in the t(5;14)(q31.1;q32.1) is another recurrent abnormality in ALL.  

Clinical Utility

Approximately 80% of ALL cases demonstrate clonal chromosome abnormalities. The remaining cases either present a normal karyotype or cannot be analyzed due to a variety of factors such as poor chromosome morphology and the apoptotic tendency of ALL blasts in culture. For this reason, FISH has become an important tool for the assessment of genetic aberrations in ALL as it can determine appropriate type of consolidation chemotherapy (risk group) according to Children's Oncology Group protocols (for pediatric ALL). 

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

Reference

1. Harrison CJ, Moorman AV, Barber KE, et al. (2005) Interphase molecular cytogenetic screening for chromosomal abnormalities of prognostic significance in childhood acute lymphoblastic leukemia: a UK Cancer Cytogenetics Group Study. Br J Haematol 129(4), 520-530.

CPT Codes

88271x14 (DNA probe, each), 88275x9 (Interphase analysis, 100-300 cells).

Contacts

Last Updated

1/18/2023