title: Three distinct subgroups of hypodiploidy in acute lymphoblastic leukaemia.
abstract: This study of children and adults with acute lymphoblastic leukaemia (ALL) is the largest series of patients with hypodiploidy (<46 chromosomes) yet reported. The incidence of 5% was independent of age. Patients were subdivided by the number of chromosomes; near-haploidy (23-29 chromosomes), low hypodiploidy (33-39 chromosomes) and high hypodiploidy (42-45 chromosomes). The near-haploid and low hypodiploid groups were characterized by their chromosomal gains and a doubled hyperdiploid population. Structural abnormalities were more frequent in the low hypodiploid group. Near-haploidy was restricted to children of median age 7 years (range 2-15) whereas low hypodiploidy occurred in an older group of median age 15 years (range 9-54). Patients with 42-45 chromosomes were characterized by complex karyotypes involving chromosomes 7, 9 and 12. The features shared by the few patients with 42-44 chromosomes and the large number with 45 justified their inclusion in the same group. Survival analysis showed a poor outcome for the near-haploid and low hypodiploid groups compared to those with 42-45 chromosomes. Thus cytogenetics, or at least a clear definition of the modal chromosome number, is essential at diagnosis in order to stratify patients with hypodiploidy into the appropriate risk group for treatment.
authors.affiliation: Leukaemia Research Fund Cytogenetics Group, Cancer Sciences Division, University of Southampton, Southampton, UK. harrison@soton.ac.uk
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Harrison
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Moorman
authors.forename: Zoë J
authors.initials: ZJ
authors.lastname: Broadfield
authors.forename: Kan L
authors.initials: KL
authors.lastname: Cheung
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Harris
authors.forename: G
authors.initials: G
authors.lastname: Reza Jalali
authors.forename: Hazel M
authors.initials: HM
authors.lastname: Robinson
authors.forename: Kerry E
authors.initials: KE
authors.lastname: Barber
authors.forename: Sue M
authors.initials: SM
authors.lastname: Richards
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Mitchell
authors.forename: Tim O B
authors.initials: TO
authors.lastname: Eden
authors.forename: Ian M
authors.initials: IM
authors.lastname: Hann
authors.forename: Frank G H
authors.initials: FG
authors.lastname: Hill
authors.forename: Sally E
authors.initials: SE
authors.lastname: Kinsey
authors.forename: Brenda E S
authors.initials: BE
authors.lastname: Gibson
authors.forename: John
authors.initials: J
authors.lastname: Lilleyman
authors.forename: Ajay
authors.initials: A
authors.lastname: Vora
authors.forename: Anthony H
authors.initials: AH
authors.lastname: Goldstone
authors.forename: Ian M
authors.initials: IM
authors.lastname: Franklin
authors.forename: Jill
authors.initials: J
authors.lastname: Durrant
authors.forename: Mary
authors.initials: M
authors.lastname: Martineau
mesh_terms: D000293:Adolescent; D000328:Adult; D000782:Aneuploidy; D002648:Child; D002877:Chromosomes, Human / Q000235:genetics*; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D011379:Prognosis; D016019:Survival Analysis