title: Non-classical karyotypic features in relapsed childhood B-cell precursor acute lymphoblastic leukemia.
abstract: Karyotype analysis of acute lymphoblastic leukemia (ALL) at diagnosis has provided valuable prognostic markers for treatment stratification. However, reports of cytogenetic studies of relapsed ALL samples are limited. We compared the karyotypes from 436 nonselected B-cell precursor ALL patients at initial diagnosis and of 76 patients at first relapse. We noticed a relative increase of karyotypes that did not fall into the classic ALL cytogenetic subgroups (high hyperdiploidy, t(12;21), t(9;22), 11q23, t(1;19), <45 chromosomes) in a group of 29 patients at relapse (38%) compared to 130 patients at presentation (30%). Non-classical cytogenetic aberrations in these 29 patients were mostly found on chromosomes 1, 2, 7, 9, 13, 14, and 17. We also describe six rare reciprocal translocations, three of which involved 14q32. The most frequent abnormalities were found in 9p (12/29 cases) and were associated with a marked decrease in the duration of the second remission, but not of the probability of 10-year event-free survival after relapse treatment. From 29 patients with non-classical cytogenetic aberrations, only 8 (28%) had been stratified to a high risk-arm on the first treatment protocol, suggesting that this subgroup might benefit from the identification of new prognostic markers in future studies.
authors.affiliation: Division of Oncology, University Children's Hospital, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland.
authors.forename: Lea A
authors.initials: LA
authors.lastname: Wehrli
authors.forename: Julia
authors.initials: J
authors.lastname: Braun
authors.forename: Luisa Nobile
authors.initials: LN
authors.lastname: Buetti
authors.forename: Nicole
authors.initials: N
authors.lastname: Hagleitner
authors.forename: Heinz
authors.initials: H
authors.lastname: Hengartner
authors.forename: Thomas
authors.initials: T
authors.lastname: Kühne
authors.forename: Sonja
authors.initials: S
authors.lastname: Lüer
authors.forename: Hulya
authors.initials: H
authors.lastname: Ozsahin
authors.forename: Maja Beck
authors.initials: MB
authors.lastname: Popovic
authors.forename: Felix K
authors.initials: FK
authors.lastname: Niggli
authors.forename: David R
authors.initials: DR
authors.lastname: Betts
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bourquin
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D007223:Infant; D007621:Karyotyping; D008297:Male; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000517:prevention & control; D012008:Recurrence; D014178:Translocation, Genetic; D016896:Treatment Outcome