F IGH MAF
t(14;16)(q32;q23), Immunoglobulin heavy chain / MAF gene
Fluorescence in situ Hybridization (FISH)
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
Whole blood and bone marrow, ship ambient
Fresh tissue, FNA or paraffin embedded tissue, ship in a Styrofoam container with a cool/refrigerated pack (Do not allow cool pack to directly contact sample)
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells
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.
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.