title: Rare MLL-ELL fusion transcripts in childhood acute myeloid leukemia-association with young age and myeloid sarcomas?
abstract: BACKGROUND
  The chromosomal translocation t(11;19)(q23;p13) with a breakpoint within subband 19p13.1 is found mainly in acute myeloid leukemia (AML) and results in the MLL-ELL fusion gene. Variations in the structure of MLL-ELL seem to influence the leukemogenic potency of the fusion in vivo and may lie behind differences in clinical features. The number of cases reported so far is very limited and the addition of more information about MLL-ELL variants is essential if the possible clinical significance of rare fusions is to be determined.
  
  
  METHODS
  Cytogenetic and molecular genetic analyses were done on the bone marrow cells of a 20-month-old boy with an unusual form of myelomonocytic AML with multiple myeloid sarcomas infiltrating bone and soft tissues. The G-banding analysis together with FISH yielded the karyotype 47,XY, +6,t(8;19;11)(q24;p13;q23). FISH analysis also demonstrated that MLL was split. RNA-sequencing showed that the translocation had generated an MLL-ELL chimera in which exon 9 of MLL (nt 4241 in sequence with accession number NM_005933.3) was fused to exon 6 of ELL (nt 817 in sequence with accession number NM_006532.3). RT-PCR together with Sanger sequencing verified the presence of the above-mentioned fusion transcript.
  
  
  CONCLUSIONS
  Based on our findings and information on a few previously reported patients, we speculate that young age, myelomonoblastic AML, and the presence of extramedullary disease may be typical of children with rare MLL-ELL fusion transcripts.
authors.affiliation: Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Nydalen, P.O.Box 4953, 0424 Oslo, Norway ; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Panagopoulos
authors.affiliation: Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Nydalen, P.O.Box 4953, 0424 Oslo, Norway ; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Gorunova
authors.affiliation: Department of Pathology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Gitte
authors.initials: G
authors.lastname: Kerndrup
authors.affiliation: Department of Pathology, Oslo University Hospital, Oslo, Norway.
authors.forename: Signe
authors.initials: S
authors.lastname: Spetalen
authors.affiliation: Laboratory Medicine Program, Department of Haematopathology, University Health Network, Toronto, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Tierens
authors.affiliation: Department of Immunology, Oslo University Hospital, Oslo, Norway.
authors.forename: Liv T N
authors.initials: LT
authors.lastname: Osnes
authors.affiliation: Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Nydalen, P.O.Box 4953, 0424 Oslo, Norway ; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Kristin
authors.initials: K
authors.lastname: Andersen
authors.affiliation: Department of Radiology, Oslo University Hospital, Oslo, Norway.
authors.forename: Lil-Sofie Ording
authors.initials: LS
authors.lastname: Müller
authors.affiliation: Department of Pediatrics, Drammen Hospital, Vestre Viken HF, Drammen, Norway.
authors.forename: Marit
authors.initials: M
authors.lastname: Hellebostad
authors.affiliation: Department of Pediatrics, Oslo University Hospital, Oslo, Norway.
authors.forename: Bernward
authors.initials: B
authors.lastname: Zeller
authors.affiliation: Section for Cancer Cytogenetics, Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital, Nydalen, P.O.Box 4953, 0424 Oslo, Norway ; Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway ; Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Sverre
authors.initials: S
authors.lastname: Heim
keywords: Acute myeloid leukemia; Chromosomal translocation; ELL; Fusion gene; MLL; Myeloid sarcoma; RNA-sequencing; t(11;19)(q23;p13)