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DNA Analysis:
Bcr/Abl Gene Rearrangement (t 9;22)
The 9;22 chromosomal translocation is found in approximately 95% of chronic myelogenous leukemia (CML) patients, 10-25% of adult acute lymphocytic leukemia (ALL) patients, and 5% of children with ALL. This translocation is the result of the transposition of the Abl proto-oncogene from chromosome 9 to the breakpoint cluster region (Bcr) gene on chromosome 22. The Bcr/Abl fusion gene forms one to three distinct chimeric mRNAs, depending on the specific breakpoint in the patient. The fusion mRNA from CML patients contains M-Bcr (major breakpoint cluster region) exon 2 or 3 fused to Abl exon II. The fusion mRNA from the majority of ALL patients contains m-Bcr (minor breakpoint cluster region) exon 1 fused to Abl exon II. Some ALL patients have breakpoints in M-Bcr which are identical to those breakpoints found in CML patients.
- Confirm the presence of the 9;22 translocation in CML and ALL patients
- Monitor patients with CML or ALL throughout the course of their disease
- Detect minimal residual disease in patients with CML or ALL following bone marrow transplantation or therapy
Our testing methodology involves RT-PCR followed by nested primer PCR analysis and gel electrophoresis to detect the Bcr/Abl fusions arising from breakpoints in exon 2 and exon 3 of M-Bcr. The PCR methodology has been shown to be highly sensitive and specific for detection of minimal residual disease.
This assay will detect the Bcr/Abl gene rearrangement in approximately 95% of patients with CML. This assay will not detect the Bcr/Abl fusion arising from a breakpoint in exon 1 of m-Bcr, which is more common in ALL.
Blood: 5 cc collected in a purple top (EDTA) or yellow top (acid citrate dextrose) vacutainer tube. Do not centrifuge or freeze. Specimen may be refrigerated or stored at room temperature.
Bone marrow: 1 - 2 cc collected in a purple top (EDTA) or yellow top (acid citrate dextrose) vacutainer tube. Do not centrifuge or freeze. Specimen may be refrigerated or stored at room temperature. The specimen should reach the laboratory within 48 hours from the time of collection.
5 - 7 days
83891, 83894, 83900, 83901 (2X), 83902, 83912
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