F BCL2; FP BCL2
IGH/BCL2; t(14;18)(q32;q21)
B-cell lymphoma (BCL), Non-Hodgkin lymphoma (NHL), Follicular lymphoma (FCL)
Fluorescence in situ Hybridization (FISH)
3-5 days
F BCL2
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
FP BCL2
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 translocation is present or absent.
A normal cell results in a two orange, two green signal pattern. In an abnormal cell containing a t(14;18), the pattern is one orange signal, one green signal and two orange/green (yellow) fusion signals representing the two derivative chromosomes.
BCL2 blocks apoptosis and maintains long-term immune responsiveness including B-cell memory. The most frequent non-random chromosome rearrangement in non-Hodgkin lymphoma (NHL) of B-cell type is t(14;18)(q32;q21), which is found in approximately 50–85% of follicular lymphomas, 15–30% of diffuse large B-cell lymphomas, and occasionally in other histological subtypes of NHL. Molecular studies of this translocation have disclosed a juxtaposition of BCL2 gene in 18q21.3 with IGH gene locus at 14q32.33. Consequently, the BCL2 gene is subjected to the control of the IGH EA enhancer leading to the over expression of the anti-apoptotic protein BCL2. FISH can detect this translocation in either interphase or metaphase cells.