F MALT; FP MALT
18q21, t(11;18)(q21;q21), MALT lymphoma-associated translocation 1 gene
Mucosa-associated lymphoid tissue (MALT lymphoma)
Fluorescence in situ Hybridization (FISH)
2.0 mL (min. 1.0 mL) peripheral blood in sodium heparin, EDTA accepted
1.0 mL (min. 0.5 mL) bone marrow in sodium heparin, EDTA accepted
5 mm^3 fresh tissue or 3.0 mL (min. 2.0 mL) FNA in MPLN RPMI media
10% neutral buffered formalin fixed paraffin embedded tissue
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; Improper fixative
A normal cell will show two fusion (yellow or orange/green fused) signals representing two intact copies of 18q21. A cell with a rearrangement involving the MALT1 gene will show a fusion signal on the normal chromosome 18 along with one orange and one green signal indicating disruption of the MALT1 gene on the rearranged chromosome.
Translocation (11;18)(q21;q21) has been associated with extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). Translocation (11;18) leads to the fusion of the apoptosis inhibitor-2 (API2) gene and the MALT lymphoma-associated translocation (MALT1) gene. However, it has been found that 18% of MALT lymphomas have t(14;18)(q32;q21) or a translocation involving the IGH and MALT1 gene. MALT lymphomas with t(11;18)(q21;q21) usually do not have additional genetic aberrations, which is in contrast to t(14;18)(q32;q21) cases. Aneuploidy is most often seen in the majority of t(14;18)(q32;q21) MALT lymphomas. >br>
FISH can detect this rearrangement in either interphase or metaphase cells.