title: Detection of dicentric chromosome (9;20) in paediatric B-cell acute lymphoblastic leukaemia: prognostic significance.
abstract: The dicentric chromosome (9;20) (dic(9;20)) is described in 2 % of childhood B-acute lymphoblastic leukaemia. Fluorescence in situ hybridization (FISH) is the most reliable method to identify dic(9;20) when compared with conventional cytogenetics. To define the prognostic importance of dic(9;20), we evaluated treatment response and patient survival. This was a retrospective study in three French university centres. Patients' clinical and laboratory characteristics and treatment response are described. Nine children with dic(9;20) have been identified since 1995. All patients had at least one poor prognostic feature either among the clinical features, the initial laboratory results or in the initial treatment response: central nervous system involvement (2/9), high median leucocyte count (≥50 G/L) (8/9) and poor response to prednisone (2/9). All patients were in complete cytological remission after induction therapy but only three had a good molecular response with minimal residual disease (MRD) <10(-3). Five out of nine patients relapsed and two died, 4 and 12 months after diagnosis, respectively. The event-free survival rate in this population was 44 % (95 % confidence interval (CI) = 0.09-0.79) and overall survival 78 % (95 % CI = 0.51-1.05). In this population, dic(9;20) is associated with a relatively poor prognosis. Patients showing dic(9;20), whether this cytogenetic abnormality is associated with other poor prognostic factors or not, should be identified at the outset in order to be offered a more intensive treatment protocol.
authors.affiliation: Pediatric Oncology and Hematology Unit, Rouen University Hospital, 1 rue de Germont 76035, Rouen, Cedex, France, mathilde.letouzey@gmail.com.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Letouzey
authors.forename: Dominique
authors.initials: D
authors.lastname: Penther
authors.forename: Catherine
authors.initials: C
authors.lastname: Roche-Lestienne
authors.forename: Brigitte
authors.initials: B
authors.lastname: Nelken
authors.forename: Catherine
authors.initials: C
authors.lastname: Devoldère
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Vannier
authors.forename: Pascale
authors.initials: P
authors.lastname: Schneider
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D059785:Karyotype; D008297:Male; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome