New recurring cytogenetic abnormalities and association of blast cell karyotypes with prognosis in childhood T-cell acute lymphoblastic leukemia: a Pediatric Oncology Group report of 343 cases

To further define the cytogenetic differences between B-cell lineage (B-lin eage) acute lymphoblastic leukemia (ALL) and T-cell lineage ALL (T-ALL) and to determine the prognostic value of cytogenetics in childhood T-ALL, the blast cell karyotypes of 343 cases of pediatric TALL, the largest series re ported to date, were evaluated. Cytogenetics were performed in a single cen tral laboratory, and the children were treated using a single Pediatric Onc ology Group protocol. Clear differences between the karyotypic characterist ics of B-lineage ALL and T-ALL were confirmed. This study suggests that the re may be survival differences associated with some T-ALL blast cell karyot ypes. Better survival is associated with only normal karyotypes and with t( 10;14) (translocation of chromosomes 10 and 14); worse survival is associat ed with the presence of any derivative chromosome. Two new recurring chromo some aberrations previously not reported in T-ALL were found: del(1)(p22) a nd t(8;12)(q13;p13). Ten aberrations found in this series, which were repor ted only once previously in T-ALL, can now be considered recurring abnormal ities in T-ALL, All 12 of these new recurring aberrations are targets for d iscovery and characterization of new genes that are important in T-cell dev elopment and leukemogenesis. (Blood. 2000; 96:2543-2549) (C) 2000 by The Am erican Society of Hematology.