BCL6 3q27 B-cell non-Hodgkin lymphoma by FISH

F BCL6


Test Synonym:
3q27



CPT Code:
88367x2 - Morphometric analysis, in situ hybridization, automated
88368 x2 - Morphometric analysis, in situ hybridization, manual


Turnaround Time:
3 days



Methodology:
Fluorescence in situ hybridization (FISH)



Specimen Requirements:

• 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 mm3 fresh tissue in MPLN RPMI media
• 3.0 ml (min. 2.0ml) FNA in MPLN RPMI media
• 10% neutral buffered formalin fixed paraffin embedded tissue


Causes for Rejection:

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


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


Storage and Handling:

• Whole blood and bone marrow ship ambient
• Fresh tissue, FNA or paraffin embedded tissue ship in a Styrofoam container with an ice pack (do not allow ice pack to directly contact sample)

Reference Range:
 FISH results indicate whether rearrangement is present or absent
In a normal cell, two fusion (orange/green, or yellow) signals will be observed representing two intact copies of chromosome 3. In a cell that has a translocation with the breakpoint within 3q27, one fusion signal, one orange signal, and one green signal will be found it indicates that the BCL6 region has been disrupted on one chromosome 3. The BCL6 probe does not indicate the second chromosome in the rearrangement. Other chromosomes probes, such as IGH at 14q32, may be available to identify the other chromosome involved in the translocation.

Indication:
 The B-cell lymphoma 6 (BCL6) gene is localized to 3q27. Rearrangements of 3q27 implicated in non-Hodgkin’s lymphoma, occur in 30-40% of diffuse large cell lymphoma and 5-15% of follicular lymphoma. The structural rearrangements include translocations and microdeletions, with about one-half of the translocations involving the immunoglobulin genes at 14q32, 2p12, and 22q13. The remaining translocations involve 3q27 with a wide variety of other chromosome partners. FISH can detect this rearrangement in either interphase or metaphase cells.

References:

  1. Cuneo A and Huret JL. (July 2000). 3q27 rearrangements in non Hodgkin lymphoma; t(3;Var)(q27;Var) in non Hodgkin lymphoma. Atlas Genet Cytogenet Oncol Haematol.
  2. Abramson JS et al. (2005). Advances in the biology and therapy of diffuse large B-cell lymphoma: moving toward a molecularly targeted approach. Blood 106(4):1164.