TEL/ETV6-AML1/RUNX1 fusion gene, t(12;21)
t(12;21)(p13;q22) reciprocal translocation is the most frequent chromosomal rearrangement in childhood B-ALL with an incidence of 25% in children (only 3% occurs in adults). The expression of the resulting fusion gene TEL-AML1 or ETV6-RUNX1, leads to expansion of the precursors of B cells giving them a great capacity for self-renewal and differentiation to mature B cells altered stages.
Unlike other translocations associated to ALL such as t(9;22) and t(4;11), the fusion gene TEL-AML1 is associated with a favorable prognosis (significantly lower relapse rate). The evaluation of this and other prognostic markers help in the selection of low toxicity therapies versus high toxicity therapies. In 90% of pediatric cases therapy is successful and, usually, in the loss of fusion transcript TEL-AML1. Relapse was associated with the reappearance of the transcription product, so this test is also useful for determining the current status of the disease.
References
- Linka et al. (2013) Blood Cancer Journal 3, e151.
- Torrano V, et al. (2013) Blood. 118: 4910–4918.
- Van Delft FW, et al. (2012) Clin. Cancer Res. 18:2754-2767.
- Fischer M, et al. Oncogene 2005; 24: 7579–7591.
