title: Favorable impact of the t(9;11) in childhood acute myeloid leukemia.
abstract: OBJECTIVE
  To determine the impact of MLL rearrangements on the outcome of children with acute myeloid leukemia (AML).
  
  
  METHODS
  We analyzed the clinical and biologic features of 298 infants and children with primary AML treated on four consecutive institutional clinical trials. The Kaplan-Meier method was used in survival analysis and the Cox proportional-hazards model was used to analyze the effect of potential prognostic factors on event-free survival (+/- 1 SE).
  
  
  RESULTS
  Molecular studies of 152 cases detected 42 with MLL rearrangements. The karyotypes of these 42 revealed the t(9;11) (15 cases), abnormalities of chromosomes 10 and 11 (nine cases), the t(11;19) (four cases), other abnormalities of 11q23 (seven cases), and miscellaneous rearrangements (seven cases). Among these 42 patients, the 15 whose leukemic cells carried the t(9;11) had a better outcome (66% +/- 15%) than the other 27 (25.9% +/- 11.2%; P =.004). Cases with the t(9;11) were also characterized by M5 AML morphology (21 of 23 cases). Of the 63 patients with M5 AML, the 21 whose leukemic cells demonstrated the t(9;11) had a better outcome (71.1% +/- 11%) than the other 42 (25.8% +/- 7.9%; P =.0004). The only independent factors indicating a favorable prognosis were presenting leukocyte count less than 50 x 10(9)/L (relative risk of relapse, 0.73; 95% confidence interval, 0.55 to 0.97; P =.03) and the t(9;11) (relative risk of relapse, 0.32; 95% confidence interval, 0.16 to 0.64; P =.002).
  
  
  CONCLUSIONS
  We conclude that the t(9;11) is the most favorable genetic factor for patients with AML treated at our institution.
authors: Department of Hematology-Oncology, St Jude Children's Research Hospital, Memphis, TN 38105-2794, USA.
authors: Jeffrey E
authors: JE
authors: Rubnitz
authors: Susana C
authors: SC
authors: Raimondi
authors: Xin
authors: X
authors: Tong
authors: Deo Kumar
authors: DK
authors: Srivastava
authors: Bassem I
authors: BI
authors: Razzouk
authors: Sheila A
authors: SA
authors: Shurtleff
authors: James R
authors: JR
authors: Downing
authors: Ching-Hon
authors: CH
authors: Pui
authors: Raul C
authors: RC
authors: Ribeiro
authors: Frederick G
authors: FG
authors: Behm
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D002869:Chromosome Aberrations; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007223:Infant; D007951:Leukemia, Myeloid / Q000188:drug therapy* / Q000235:genetics* / Q000276:immunology; D008297:Male; D016016:Proportional Hazards Models; D016019:Survival Analysis; D016896:Treatment Outcome