bcr-2 Translocation Detection for Lymphoma

Test Includes:

Major breakpoint region (MBR) and minor cluster region (MCR)

Special Instructions:

Pathologist consultation is available Monday through Friday.

Specimen:

Whole blood, bone marrow, lymph node, or other tissue

Volume:

7 mL whole blood or 1-2 cc bone marrow or 0.5-1.0 g tissue

Minimum Volume:

3 mL whole blood

Container:

Whole blood or bone marrow in lavender-stopper (EDTA) tubes, lymph node or tissue in lymph node transport bottle

Collection:

Specimens should arrive in the laboratory within 48 hours of collection. Indicate date and time of collection on the test request form.

Storage:

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

Use:

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.

Methodology:

Polymerase chain reaction (PCR) and allele-specific oligonucleotide (ASO) analysis

Additional Information:

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 over expressed, 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.