F BCL6; FP BCL6
BCL6 gene; 3q27 rearrangement
B-cell lymphoma, Non-Hodgkin lymphoma (NHL), Diffuse large B cell, Follicular lymphoma
Fluorescence in situ Hybridization (FISH)
5mL peripheral blood in sodium heparin
3mL bone marrow in sodium heparin
Fixed cytogenetically prepared cells in sterile centrifuge tube with pellet visible in 3:1, Methanol:Acetic Acid
FFPE tissue is acceptable for FISH analysis. Preferred fixative is 10% neutral buffered formalin. Tissues preserved in B5 fixative or decalcified are usually not suitable for FISH. Tumor sections cut 3-5 µm thick and mounted on positively charged organosilane coated (silanized) slides work well. Request several unstained sections (two for each probe) and one H&E stained slide
4°C to 25°C during transit, but specimens may be transported on refrigerated gel packs. Do not allow the gel pack to come in contact with the specimen. Do not freeze. Extreme temperatures should be avoided.
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative
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.
The B-cell lymphoma 6 (BCL6) gene is localized to 3q27. Rearrangements of 3q27 may be seen in case diffuse large B-cell lymphoma (30-40%) and follicular lymphoma (5-15%). 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.