Services: Hematopathology : Bcr-2 Translocation

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 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.

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