header
 

BCR-ABL Translocation (9,22)

F BCR-ABL

Test Synonym:

Philadelphia chromosome

CPT Code:

88367 x2 - Morphometric analysis

Turnaround Time:

3 days

Methodology:

Fluorescence in situ hybridization (FISH)

Specimen Requirements:

  • 5.0ml (min. 3.0 ml) peripheral bloodin sodium heparin preferred, EDTA accepted
  • 3.0ml (min 1.0ml) bone marrow in sodium heparin preferred, EDTA accepted
  • 5mm3 fresh tissue in MPLN RPMI media
  • 3.0ml (min 2.0ml) FNA in MPLN RPMI  media

    • Causes for Rejection:

    Clotted specimen

    Specimen exposed to extreme temperature

    Anticoagulant toxic to cells

    Insufficient number of cells

    Specimen Stability:

  • Peripheral blood and bone marrow stable at 18-25°C for 72 hours
  • Fresh tissue or FNA at 2°-8°C stable for 72 hours

    • Storage and Handling:

    Whole blood and bone marrow ship ambient

    Fresh tissue or FNA ship in a styrofoam container with an ice pack (do not allow ice pack to directly contact sample)


    Reference Range:

    FISH analysis detects presence or absence of t(9;22)

    Indication:

    The Philadelphia chromosome results from a translocation between 9q34(ABL) and 22q11.2(BCR).  The chromosome rearrangement leads to a hybrid gene that produces a protein with increased kinase activity.  The Philadelphia chromosome is present in virtually all cases of chronic myelogenous leukemia (CML), at least at the molecular level, and is found to a lesser degree in acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML).  Presence of the t(9;22) is associated with a poor prognosis in both ALL and AML. In CML progression to an accelerated phase or to blast crisis is often preceded by the appearance of secondary chromosome changes such as +8, i(17q), +der(22) and +19.  Disease progression in AML and ALL is accompanied by similar secondary aberrations.   FISH for BCR-ABL detects the typical t(9;22) as well as cryptic 9;22 rearrangements.  Additional FISH studies can identify secondary chromosome changes.

    References:

    1. Wang et al. (2004). Determination of secondary chromosomal aberrations of chronic myelocytic leukemia. Cancer Genet Cytogenet 153(1):53.
    2. Keung et al. (2004). Philadelphia chromosome positive myelodysplastic syndrome and acute myeloid leukemia – retrospective study and review of literature. Leukemia Res 28(6):579.
    3. Haigh. (2004). Fluorescence in situ hybridization characterization of different cryptic BCR-ABL rearrangements in chronic myeloid leukemia. Cancer Genet Cytogenet 155(2):132.