OVERVIEW
MALT lymphoma is a B-cell lymphoma arising from cells in the marginal zone of the mucosa-associated lymphoid tissue (MALT). It accounts for about 7-8% of B-cell lymphomas and about 50% of primary gastric lymphomas. Approximately half of MALT lymphoma cases involve the gastrointestinal (GI) tract, with ~85% of those involving the stomach. Other common sites include salivary gland, lung, head and neck, ocular adnexa, skin, thyroid, and breast.
There are four main chromosomal translocations associated with MALT lymphoma: t(1;14)(p22;q32), t(11;18)(q21;q21), t(14;18)(q32;q21), and t(3;14)(p14.1;q32). The two most common of these involve the MALT1 gene (18q21.3). The t(11;18) translocation occurs in up to 40% of MALT lymphomas and is mainly detected in pulmonary and gastric tumours, and the t(14;18)(q32;q21) occurs in up to 20% of cases and is mainly detected in ocular adnexa and salivary gland tumours.
TEST REQUIREMENTS
- Completed CGL Lymphoid Testing requisition form
- FFPE Tumour specimen (see Specimen Guidelines, Cytogenetics FISH FFPE test type)
- An H&E stained slide with the tumour region circled, and the estimated % tumour content written in the Tumour Content field of the requisition. NOTE: A minimum of 10% tumour and at least 200 nuclei is required.
- Specimen block and/or at least one unstained slide for each probe requested.
- See our FFPE Guidelines for additional details.
NOTE: FISH analysis on a bone marrow aspirate for the purposes of staging is not performed, unless a lymph node is not available
RESULTS REPORTING
Specimens are reported as Positive for a rearrangement, Negative for a rearrangement
TURN-AROUND TIME
Results are reported within fourteen days from receipt of specimen and completed requisition form.
METHOD
FISH analysis is performed on the provided FFPE tissue using the MALT1 (18q21.3) dual-colour, break apart probe (Vysis).
