F BURKITT; FP BURKITT
C-MYC 8q24, BCL2 t(14;18), BCL6 3q27
"double hit" B-cell 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
This small, multiprobe panel contributes to the distinction of Burkitt’s from large B-cell lymphoma on problematic specimens demonstrating borderline morphologic or immunophenotypic features, limited sample volume, or zero to low probability for successful karyotyping. Burkitt’s lymphoma characteristically demonstrates a very high Ki67 staining index, strong CD10, and positive bcl-6 staining with negative staining for bcl-2. Burkitt’s lymphomas typically reveal MYC translocation partnered to Ig heavy or light chain genes in the background of an otherwise simple karyotype. Rarely, Burkitt’s lymphomas may lack MYC translocation.
Among large B-cell lymphomas, MYC translocation is demonstrated in a small but significant subset, almost always in the background of a complex karyotype, presumably representing secondarily acquired genetic change. Frequently, these MYC+ large B-cell lymphomas are also positive for BCL2 or BCL6 rearrangements. Incomplete clinical evidence suggests that MYC+ large B-cell lymphomas may benefit from Burkitt-like chemotherapeutic regimens.
When confronted with fresh or paraffin embedded tissue specimens containing CD10+ Ki67+(high) bcl2- B-cell neoplasia, this multiprobe FISH panel often facilitates distinction of Burkitt’s from large B-cell lymphoma.