Test Code

F IGH MAF

Test Synonyms

t(14;16)(q32;q23), Immunoglobulin heavy chain / MAF gene

Associations

Myeloma, MGUS

Methodology

Fluorescence in situ Hybridization (FISH)

Turnaround Time

3-5 days

Specimen Requirements

5mL peripheral blood in sodium heparin
3mL bone marrow in sodium heparin
Fixed cytogenetically prepared cells in sterile centrifuge tube with pellet visible in 3:1, Methanol:Acetic Acid

Specimen Stability

Storage & Handling

4°C to 25°C during transit, but specimens may be transported on refrigerated gel packs. Do not allow the gel pack to come in contact with the specimen. Do not freeze. Extreme temperatures should be avoided.

Causes for Rejection

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

Reference Range

In a normal cell, a two orange, two green signal pattern will be observed. In an abnormal cell containing the t(14;18) translocation, a one orange (MAF), one green (IGH), and two fusion (IGH/MAF and MAF/IGH) signals observed.

Description

The t(14;16)(q32;q23) is detectable in 2–10% of patients with plasma cell myeloma and in about 25% of myeloma cell lines. The t(14;16)(q32;q23) is difficult to detect by conventional karyotypes. Although some studies report a low prevalence of the t(14;16) in newly diagnosed patients, other studies reveal that a small percentage of patients show the t(14;16) at the time of initial diagnosis. Translocation (14;16)(q32;q23) has also been described in MGUS.
FISH can detect this rearrangement in either interphase or metaphase cells.

References

1. Fonseca et al. (2004). Genetics and cytogenetics of multiple myeloma: A workshop report. Cancer Res. 64:1546.
2. Hideshima et al. (2004). Advances in biology of multiple myeloma: clinical applications. Blood. 104:607.
3. Pratt G. (2002). Molecular aspects of multiple myeloma. J Clin Pathol: Mol Pathol. 55:273.