Real-time RT-PCR for quantitative detection of the t(12;21) ETV6-RUNX1 fusion transcript (formerly called TEL-AML1). Analytical sensitivity is 1 tumor cell in 100,000 normal cells. Positive results are reported as a percentage ratio between quantities of transcript of t(12;21) and the sum of t(12;21) plus a control gene.
The (12;21) translocation occurs in approximately 25-30% of pediatric B-cell acute lymphoblastic leukemia (B-ALL), but is rare in adult cases. This translocation is associated with a high rate of complete remission and good outcome. This assay is recommended for monitoring therapy effectiveness and for the detection of minimal residual disease (MRD) after confirming baseline detection. Due to breakpoint variations, this assay cannot detect all ETV6-RUNX1 translocations and FISH should be used if diagnostic confirmation is required.
- Peripheral blood: 5 mL in EDTA tube.
- Bone marrow: 2 mL in EDTA tube.
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. Ship same day as drawn whenever possible; specimens <72 hours old preferred.