Fish analysis of tel-aml 1 in childhood leukaemia in a local multiracial asian population

Acute Lymphoblastic Leukaemia (ALL) is the most common cancer in childhood. Chromosomal rearrangements occur in approximately 75% of children with ALL, most frequently involving chromosomes 12 and 21. The helix-loop-helix domain of the TEL gene on chromosome 12pl3 fuses to the DNA-binding and transactivation domain of the AML 1 gene on chromosome 21q22. Molecular studies have demonstrated thatTel-AML 1 occurs in approximately 25% of B-precursor ALL and is associated with an excellent short-term prognosis in paediatric ALL. A commercially available FISH Tel/AML 1 dual colour DNA probe detects this translocation efficiently on both metaphase and interphase nuclei. As routine cytogenetics is not reliable in detecting t(12:21)(pl3:q22), FISH is an invaluable tool in identifying this group of good risk patients who may be candidates for less intensive treatment. We thus undertook this prospective study to evaluate the frequency of TELAML I in our local multiracial Asian population and its impact on prognosis. We present our preliminary results. To date, 6 patients (27%) have been identified as positive for this fusion. Of note, 2 of these patients are high risk by the standard definition using presenting total white counts. We hope that this pilot study will help to establish a more accurate risk stratification of patients and hence deliver the most appropriate treatment with minimal morbidity.

Duke Scholars

Author Patrick Tan Medicine, Medical Oncology