title: Is trisomy 5 a distinct cytogenetic subgroup in acute lymphoblastic leukemia?
abstract: Acute lymphoblastic leukemia (ALL) is characterized by recurrent clonal chromosomal abnormalities, with numerical abnormalities being a common feature especially among children. Case reports in the literature suggest that one such recurrent numerical abnormality is the gain of chromosome 5 (trisomy 5) as the sole abnormality; due to the rarity of these cases, however, little is known about their incidence, clinical features, and prognosis. We have identified seven cases with trisomy 5 as the sole or primary chromosomal abnormality from a total of 3,400 karyotypes collected in the Leukaemia Research Fund UK Cancer Cytogenetics Group Karyotype Database. All cases had a precursor B-cell immunophenotype and there was a male predominance. Five patients were children aged between 7 and 14 years old. Four of the six patients with a reasonable follow-up period had relapsed, indicating a poor prognosis. We conclude that trisomy 5 as the sole numerical abnormality occurs predominantly in older children, may be associated with a poor outcome, and may represent a distinct, albeit rare, cytogenetic subgroup in ALL.
authors.affiliation: Cancer Sciences Division, University of Southampton, MP 822, Duthie Building, Southampton General Hospital, SO16 6YD Southampton, UK.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Harris
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Harrison
authors.forename: Mary
authors.initials: M
authors.lastname: Martineau
authors.forename: Kerry E
authors.initials: KE
authors.lastname: Taylor
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Moorman
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002895:Chromosomes, Human, Pair 5; D020732:Cytogenetic Analysis; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D014314:Trisomy