bcr-2 Translocation Detection for Lymphoma
Major breakpoint region (MBR) and minor cluster region (MCR)
Pathologist consultation is available Monday through Friday.
Whole blood, bone marrow, lymph node, or other tissue
7 mL whole blood or 1-2 cc bone marrow or 0.5-1.0 g tissue
3 mL whole blood
Whole blood or bone marrow in lavender-stopper (EDTA) tubes, lymph node or tissue in lymph node transport bottle
Specimens should arrive in the laboratory within 48 hours of collection. Indicate date and time of collection on the test request form.
Maintain specimen at room temperature. Some specimen types may be submitted frozen; call the laboratory for instructions.
Causes for Rejection:
Specimen frozen; specimen in formalin or other fixative; clotted specimen; hemolysis; blood more than 72 hours old; bone marrow aspirates older than 5 days; bags or bottles of body fluid or bronchial washings
Detect bcl-2 rearrangement in B-cell lymphomas. The bcl-2 rearrangement is found in follicular lymphomas, large diffuse B-cell lymphomas, and undifferentiated lymphomas. Usually this rearrangement involves a reciprocal translocation with the JH region on chromosome 14, thus forming t14;18. Clinical use includes diagnosis and characterization of lymphomas, determining disease dissemination, and detecting minimal residual disease.
Polymerase chain reaction (PCR) and allele-specific oligonucleotide (ASO) analysis
The protein coded for by the oncogene, bcl-2, acts by suppressing the cell death program or apoptosis. Apoptosis occurs in all cells but is especially important in immune and hematopoietic cells, which have a high cell turnover rate. When the bcl-2 gene is overexpressed, it will act to prevent apoptosis and possibly may render cells resistant to cell death by irradiation and certain chemotherapeutic agents. A translocation between immunoglobulin genes (heavy chain or light chain genes) and bcl-2 results in the overexpression of bcl-2 protein and thus the expansion of B cells due to halting cell death. This type of translocation is found in 80% to 90% of follicular lymphomas, 30% of large diffuse lymphomas, and 50% of undifferentiated lymphomas.