title: Derivative chromosome 9 deletions are a significant feature of childhood Philadelphia chromosome positive acute lymphoblastic leukaemia.
abstract: Deletions from the derivative chromosome 9, der(9), of the translocation, t(9;22)(q34;q11), at the site of the ABL/BCR fusion gene, have been demonstrated by fluorescence in situ hybridisation (FISH), in both Philadelphia chromosome (Ph)-positive chronic myeloid leukaemia (CML) and acute lymphoblastic leukaemia (ALL). In CML they occur in 10-15% of cases and appear to indicate a worse prognosis, whereas in ALL, the situation is unclear. This study presents the findings of dual fusion FISH used to detect such deletions in a series of 27 BCR/ ABL-positive childhood ALL patients. Metaphase FISH was essential for the accurate interpretation of interphase FISH signal patterns. Three cases (11%) had a single fusion signal, resulting from deletions of the der(9). Three other patients with variant translocations and one with an insertion, also had a single fusion, but with no evidence of deletions. Gain of a fusion in approximately one-third of patients indicated a second Ph, which appears to be a diagnostic marker of Ph-positive ALL. This study shows that the incidence of deletions from the der(9) in childhood ALL is at least as high as that reported for CML.
authors.affiliation: Leukaemia Research Fund Cytogenetics Group, Cancer Sciences Division, University of Southampton, Southampton, UK.
authors.forename: H M
authors.initials: HM
authors.lastname: Robinson
authors.forename: M
authors.initials: M
authors.lastname: Martineau
authors.forename: R L
authors.initials: RL
authors.lastname: Harris
authors.forename: K E
authors.initials: KE
authors.lastname: Barber
authors.forename: G R
authors.initials: GR
authors.lastname: Jalali
authors.forename: A V
authors.initials: AV
authors.lastname: Moorman
authors.forename: J C
authors.initials: JC
authors.lastname: Strefford
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Broadfield
authors.forename: K L
authors.initials: KL
authors.lastname: Cheung
authors.forename: C J
authors.initials: CJ
authors.lastname: Harrison
mesh_terms: D002648:Child; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015994:Incidence; D007399:Interphase; D007621:Karyotyping; D008677:Metaphase; D010677:Philadelphia Chromosome; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology / Q000235:genetics*; D011379:Prognosis
chemical_list: C406060:abl-bcr fusion protein, human; D016044:Fusion Proteins, bcr-abl