TEL AML1 Fusion, T(12;21)(P13;Q22), FISH

What is the TEL-AML test used for?

The TEL-AML test detects the fusion gene created by a translocation between chromosomes 12 and 21, a hallmark of certain cases of acute lymphoblastic leukemia (ALL). The TEL (ETV6) gene fuses with the AML1 (RUNX1) gene, creating an abnormal protein that affects normal blood cell development and contributes to leukemogenesis.


Who should undergo this test?

This test is primarily used in children and some adults diagnosed with ALL. Identifying the TEL-AML fusion has both diagnostic and prognostic significance. Patients with this genetic alteration often respond better to treatment and have a favorable prognosis compared to those without it.


How is the TEL-AML fusion detected?

The test is typically performed on bone marrow or peripheral blood samples. Molecular techniques like reverse transcriptase polymerase chain reaction (RT-PCR) or fluorescence in situ hybridization (FISH) are used to detect the presence of the TEL-AML fusion transcript or chromosomal translocation, respectively.


What do positive test results mean?

A positive result confirms the presence of the TEL-AML1 fusion, supporting a diagnosis of B-cell precursor ALL. This finding helps in classifying the leukemia subtype, guiding treatment decisions, and providing prognostic information. It may also influence monitoring strategies during remission and relapse.


Can this test be used to monitor disease progression or relapse?

Yes, quantitative PCR methods allow for monitoring minimal residual disease (MRD) in patients with the TEL-AML fusion. Detecting even small amounts of the fusion gene post-treatment can indicate early signs of relapse, prompting timely therapeutic intervention.