Tests Detect Chromosomal Abnormalities Associated With Leukemia

Six DNA tests have been introduced in Europe for use by diagnostic laboratories in identifying chromosomal abnormalities associated with certain forms of leukemia, a cancer of the white blood cells originating in the bone marrow.

The tests are based on fluorescence in situ hybridization technology (FISH) and employ DNA probes used to detect genetic abnormalities, such as extra or rearranged chromosomes, common in patients with acute lymphocytic leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL). DNA probes are molecules stained with fluorescent dyes that recognize and bind to specific target molecules in patient samples. The fluorescent probes can be viewed under a special microscope, enabling the detection of chromosome gains, deletions, or translocations.

The FISH tests are intended to supplement conventional cytogenetics (the analysis of chromosomes) and in some cases provide additional information not detected by other test methods. Conventional cytogenetics, for example, may indicate if large chromosome changes have occurred, whereas the FISH method targets specific, more cryptic chromosome defects known to be associated with cancers.

The following six probes have received CE mark certification, allowing them to be commercially marketed in the European Union: the VysisLSI p53/LSI ATM and LSI D13S319/LSI 13q34/CEP 12 Multi-Color Probe Sets; Vysis LSI BCR/ABL Dual Color, Dual Fusion Translocation Probe Set (20 assays and 50 assays); Vysis LSI BCR/ABL ES Dual Color Translocation Probe Set; Vysis LSI BCR/ABL Dual Color, Single Fusion Translocation Probe Set; Vysis LSI MLL Dual Color, Break Apart Rearrangement Probe; and Vysis LSI 21 SpectrumOrange Probe. The six probes are already available in the United States.

These products represent the first in a series of CE-marked DNA probes that Abbott Molecular (Des
Plaines, IL, USA) expects to launch in Europe in the coming months. Future probes will be offered for a variety of applications in cancer and genetic testing.

Certain genetic aberrations can be important indicators of whether a patient has a particularly aggressive form of leukemia or whether they will respond to certain therapies, said Timothy Stenzel, M.D., Ph.D., medical director, Abbott Molecular. Abbott's FISH technology helps physicians diagnose different leukemias that may look similar but have different genetic abnormalities and therefore may require different treatment.


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