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IGH/MALT1 t(14;18) by FISH

Test Code

F IGH MALT; FP IGH MALT1

Test Synonyms

t(14;18)(q32;q21), Immunoglobulin heavy chain / Mucosa associated lymphoid tissue lymphoma translocation gene 1

Associations

MALT lymphoma

Methodology

Fluorescence in situ Hybridization (FISH)

Turnaround Time

3-5 days

Specimen Requirements

F IGH MALT1
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 medi

FP IGH MALT1
10% neutral buffered formalin fixed paraffin embedded tissue

 

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

Storage & Handling

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)

Causes for Rejection

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

Reference Range

In a normal cell, a two orange, two green signal pattern is observed reflecting two intact copies of MALT1 and IGH, respectively. In an abnormal cell containing only the t(14;18)(q32;q21) translocation, a one orange, one green, and two fusion signal pattern is observed.

Description

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 seen in the majority of t(14;18)(q32;q21) MALT lymphomas. 
FISH can detect this rearrangement in either interphase or metaphase cells.

References
  1. Bertoni F et al. (2006). Delving deeper into MALT lymphoma biology. J Clin Invest. 116(1):22.
  2. Cavalli F et al. (2001). MALT lymphomas. Hematology. (1):241.
  3. Streubel B et al. (2003). t(14;18)(q32;q21) involving IGH and MALT1 is a frequent chromosomal aberration in MALT lymphoma. Blood. 101(6):2335.
  4. Cook JR. (2003). T(14;18)(q32;q21) involving MALT1 and IGH genes in an extranodal diffuse large B-cell lymphoma. Hum Pathol. 34(11):1212.