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Myelodysplastic Syndrome FISH Panel by Fluorescence In Situ Hybridization (FISH) Analysis

FISH, MDS, genetic, GMDS2, Monosomy 5/5q deletion, Monosomy 7/7q deletion, trisomy 8, chromosome 20q deletion, chromosome 11q deletion (MLL gene), Monosomy 13/chromosome 13q deletion, RPN1/MECOM, p53/CEP17

Test Codes

EPIC: LAB6672

Department

Cytology

Specimen Collection Criteria

Collect: Peripheral blood or 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: 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 two 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 positive FISH result indicates the presence of the chromosome abnormality. A good prognosis is predicted with a normal karyotype, del(5q) or del(20q); an intermediate prognosis with trisomy 8; and a poor prognosis with chromosome 7 abnormalities and MLL gene deletion.

Clinical Utility

Bone marrow cytogenetic analysis is a standard practice in the evaluation of a patient with suspected myelodysplastic syndrome (MDS) and is considered an independent predictor of clinical outcome, overall survival, and progression to acute leukemia. Conventional cytogenetic analysis has identified chromosome abnormalities in approximately 40-70% of de novo MDS cases and in 95% of therapy-related MDS at diagnosis, with no abnormality specific for a particular MDS subtype with the exception of the chromosome 5q deletion. Recurrent chromosome changes in MDS include loss of chromosomes 5 or 7, deletions of chromosomes 5q or 7q, inv(3)(q21q26)/t(3;3)(q21;q26) trisomy 8, p53 gene deletion, and chromosome 20q deletion. Loss of the Y chromosome is also relatively common in MDS, but this is likely an age-related artifact in most patients. 

The primary utility of FISH analysis in MDS is based on the finding that 15-20% of MDS patients demonstrate a normal karyotype, yet possesses one or more clonal abnormalities of prognostic and/or therapeutic significance when analyzed by FISH. In addition, the subset of MDS patients positive for one or more abnormalities by FISH but with a normal karyotype has demonstrated an increase in bone marrow blasts, an increased rate of leukemic transformation, and a poorer prognosis. Based on this and other studies, most advocate the use of an MDS FISH panel on the diagnostic specimen. The MDS FISH panel includes probes to detect -5/5q-, -7/7q-, trisomy 8, inv(3)(q21q26) or t(3;3)(q21;q26), chromosome 20q deletion, chromosome 11q deletion (MLL gene), p53 gene deletion, and chromosome 13q deletion.

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

Reference

1. Bernasconi P et al (2006): Clinical relevance of cytogenetics in myelodysplastic syndromes. Ann NY Acad Sci 1089: 395-410.
2. Rigolin GM et al (2001): Clinical importance of interphase cytogenetics detecting occult chromosome lesions in myelodysplastic syndromes with normal karyotype. Leukemia 15: 1841-1847.

CPT Codes

88271x13 DNA probe, each, 88275x7 Interphase analysis, 100-300 cells.

Contacts

Last Updated

12/30/2022