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EGR1 5q deletion, monosomy 5 by FISH

Test Code

F EGR1

Test Synonyms

5q-, -5/del(5)(q31), deletion 5q31

Associations

5q- syndrome, Myelodysplasia (MDS), Myeloproliferative disease (MPD), Acute myelogenous leukemia (AML);
Lenolidomide

Methodology

Fluorescence in situ Hybridization (FISH)

Turnaround Time

3-5 days

Specimen Requirements

2.0 mL (min. 1.0 mL) peripheral blood in sodium heparin preferred, EDTA accepted
1.0 mL (min. 0.5 mL) bone marrow in sodium heparin preferred, EDTA accepted
5 mm^3 fresh tissue or 3.0 mL (min. 2.0 mL) FNA in MPLN RPMI media

Specimen Stability
Peripheral blood and bone marrow stable at 18-25°C for 72 hours
Fresh tissue or FNA at 2-8°C stable for 72 hours
Storage & Handling

Whole blood and bone marrow, ship ambient
Fresh tissue and FNA ship in a Styrofoam container with a cool/refrigerated pack (Do not allow cool pack to directly contact sample)

Causes for Rejection

Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells

Description

An interstitial deletion of chromosome 5, del(5q), is associated with MDS/MPD and AML. Involvement of chromosome 5 is found in 40% of therapy-related myeloid disorders, whereas it is found in only 5–7% of de novo AML. Deletions of the long arm of chromosome 5 could vary considerably, and involvement of all bands between 5q11 and 5q33~q34 have been identified. The frequent loss of 5q suggests that important tumor suppressor genes map to this genomic segment. Previous studies have indicated that a critical tumor suppressor gene for AML and more aggressive forms of MDS is located in 5q31. A distinct common deletion region for the 5q2 syndrome was localized to 5q32. However, most patients with a 5q2 syndrome or AML and MDS with del(5q) have large deletions. Monosomy 5 usually appears as part of a complex karyotype involving several other chromosomes and rarely as a sole abnormality. Monosomy 5 has been considered less likely to be a primary karyotypic abnormality. FISH can detect these abnormalities in either interphase or metaphase cells.

The so-called “5q- syndrome” associated with isolated deletion of chromosome 5 in MDS is a favorable prognostic indicator. In contrast, complex karyotypes with deletion of chromosome 5 in MDS are associated with an adverse outcome. Deletion of 5q or monosomy 5 in AML, with or without other chromosome changes, is also associated with a poor prognosis. Other chromosome changes commonly occurring with 5q- are monosomy 7/7q-, trisomy 8, and 20q-. These changes can be detected by using individual FISH probes or as part of the MDS probe panel.

FISH for abnormalities of chromosome 5 can be performed on interphase or metaphase cells.

References
  1. Anderson C et al. (2002). Cancer Genetics and Cytogenetics. 136:101–107.
  2. Royer-Pokora B et al. (2006). Cancer Genetics and Cytogenetics. 167:66–69.