OVERVIEW
Follicular lymphoma (FL) is a neoplasm composed of germinal centre B-cells and it forms in at least a partially follicular pattern. It accounts for about 20% of all lymphomas and occurs almost exclusively in adults (>18 years). It primarily affects the lymph nodes, but can also involve the spleen, bone marrow, peripheral blood, and Waldeyer ring. FISH is used to identify rearrangements of BCL2, primarily the t(14;18)(q32;q21) translocation involving IGH which is identified in 80% of cases and BCL6 rearrangements which are identified in up to 15% of FL cases.
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, or Negative for a rearrangement – extra signals
- A negative result for BCL2 or BCL6 neither precludes the existence of such a rearrangement nor does it exclude a diagnosis of FL
- BCL2 and BCL6 rearrangements are common in FL but may be identified in other mature B-cell neoplasms
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 following the dual-colour, break apart probes (Vysis): BCL2 (18q21) and BCL6 (3q27).
