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Medline ® Abstract for Reference 123

of 'Overview of the treatment of acute lymphoblastic leukemia in children and adolescents'

123
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An international study of intrachromosomal amplification of chromosome 21 (iAMP21): cytogenetic characterization and outcome.
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Harrison CJ, Moorman AV, Schwab C, Carroll AJ, Raetz EA, Devidas M, Strehl S, Nebral K, Harbott J, Teigler-Schlegel A, Zimmerman M, Dastuge N, Baruchel A, Soulier J, Auclerc MF, Attarbaschi A, Mann G, Stark B, Cazzaniga G, Chilton L, Vandenberghe P, Forestier E, Haltrich I, Raimondi SC, Parihar M, Bourquin JP, Tchinda J, Haferlach C, Vora A, Hunger SP, Heerema NA, Haas OA
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Leukemia. 2014 May;28(5):1015-21. Epub 2013 Oct 29.
 
Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of childhood B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). To date, fluorescence in situ hybridisation (FISH), with probes specific for the RUNX1 gene, provides the only reliable detection method (five or more RUNX1 signals per cell). Patients with iAMP21 are older (median age 9 years) with a low white cell count. Previously, we demonstrated a high relapse risk when these patients were treated as standard risk. Recent studies have shown improved outcome on intensive therapy. In view of these treatment implications, accurate identification is essential. Here we have studied the cytogenetics and outcome of 530 iAMP21 patients that highlighted the association of specific secondary chromosomal and genetic changes with iAMP21 to assist in diagnosis, including the gain of chromosome X, loss or deletion of chromosome 7, ETV6 and RB1 deletions. These iAMP21 patients when treated as high risk showed the same improved outcome as those in trial-based studies regardless of the backbone chemotherapy regimen given. This study reinforces the importance of intensified treatment to reduce the risk of relapse in iAMP21 patients. This now well-defined patient subgroup should be recognised by World Health Organisation (WHO) as a distinct entity of BCP-ALL.
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Leukaemia Research Cytogenetics Group, Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK.
PMID