title: [MLL rearrangements in acute leukemias].
abstract: OBJECTIVE
  In present study we have studied MLL rearrangements in a serie of acute myeloid, lymphoblastic and biphenotypic leukaemias.
  
  
  METHODS
  We analyzed a total of 11 cases: 9 acute myeloid leukaemias (M4 and M5 subtypes in FAB classification), 1 lymphoid leukaemia, and 1 acute biphenotypic leukaemia. We studied bone marrow samples from all patients by using conventional cytogenetic techniques and fluorescence in situ hybridization (FISH) with an MLL probe. We also analyzed the correlation between clinical features and genetic results.
  
  
  RESULTS
  Cells from 6 patients showed to contain MLL rearrangements and these arose in all types of leukaemias included in this study. Some MLL rearrangements were detected by FISH in kariotypically normal cases or without cytogenetic evidence of 11q23 aberration. MLL gene duplication has been observed in two cases with M4 and biphenotypic leukaemia, respectively. The presence of MLL gene rearrangements does not shape a group of patients with a common clinical pattern.
  
  
  CONCLUSIONS
  MLL rearrangements occurs in a wide variety of leukemias. These rearrangements should be screened by FISH techniques, taking into account that gene duplications could arise in cases with normal karyotype. MLL rearrangements appear to have a considerable clinicopathologic heterogeneity.
authors.affiliation: Servicio de Genética, Fundación Jiménez Díaz, Madrid.
authors.forename: M
authors.initials: M
authors.lastname: Urioste
authors.forename: E
authors.initials: E
authors.lastname: Arranz
authors.forename: B
authors.initials: B
authors.lastname: Martínez-Delgado
authors.forename: C
authors.initials: C
authors.lastname: Soto
authors.forename: A
authors.initials: A
authors.lastname: Román
authors.forename: I
authors.initials: I
authors.lastname: Pérez
authors.forename: M
authors.initials: M
authors.lastname: Mayayo
authors.forename: C
authors.initials: C
authors.lastname: Pérez-Pons
authors.forename: A
authors.initials: A
authors.lastname: Barroso
authors.forename: J
authors.initials: J
authors.lastname: Benítez
mesh_terms: D000328:Adult; D002880:Chromosomes, Human, Pair 11; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015479:Leukemia, Myelomonocytic, Acute / Q000235:genetics*; D009857:Oncogenes; D014178:Translocation, Genetic