title: A novel RT-qPCR assay for quantification of the MLL-MLLT3 fusion transcript in acute myeloid leukaemia.
abstract: OBJECTIVE
  Patients with acute myeloid leukaemia (AML) of the monocytic lineage often lack molecular markers for minimal residual disease (MRD) monitoring. The MLL-MLLT3 fusion transcript found in patients with AML harbouring t(9;11) is amenable to RT-qPCR quantification but because of the heterogeneity of translocation break points, the MLL-MLLT3 fusion gene is a challenging target. We hypothesised that MRD monitoring using MLL-MLLT3 as a RT-qPCR marker is feasible in the majority of patients with t(9;11)-positive AML.
  
  
  METHODS
  Using a locked nucleic acid probe, we developed a sensitive RT-qPCR assay for quantification of the most common break point region of the MLL-MLLT3 fusion gene. Five paediatric patients with t(9;11)-positive AML were monitored using the MLL-MLLT3 assay.
  
  
  RESULTS
  A total of 43 bone marrow (BM) and 52 Peripheral blood (PB) samples were collected from diagnosis until follow-up. Two patients relapsed, and both were MRD positive in BM after first induction course. A total of three relapses occurred, and they were detected by RT-qPCR 3 wks before haematological relapse was diagnosed.
  
  
  CONCLUSIONS
  This MLL-MLLT3 RT-qPCR assay could be useful in MRD monitoring of a group of patients with AML who often lack reliable MRD markers.
authors.affiliation: Department of Paediatrics, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Lotte
authors.initials: L
authors.lastname: Abildgaard
authors.forename: Hans Beier
authors.initials: HB
authors.lastname: Ommen
authors.forename: Birgitte
authors.initials: B
authors.lastname: Lausen
authors.forename: Henrik
authors.initials: H
authors.lastname: Hasle
authors.forename: Charlotte Guldborg
authors.initials: CG
authors.lastname: Nyvold
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics*; D001853:Bone Marrow / Q000737:chemistry; D002648:Child; D002675:Child, Preschool; D002880:Chromosomes, Human, Pair 11; D002899:Chromosomes, Human, Pair 9; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000737:chemistry; D018365:Neoplasm, Residual / Q000175:diagnosis* / Q000188:drug therapy / Q000235:genetics; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D012008:Recurrence; D012074:Remission Induction; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D014178:Translocation, Genetic
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D015342:DNA Probes; C529663:MLL-MLLT3 fusion protein, human; D009841:Oligonucleotides; D015514:Oncogene Proteins, Fusion; D012333:RNA, Messenger; C477371:locked nucleic acid
keywords: MLL-MLLT3; acute myeloid leukaemia; minimal residual disease; RT-qPCR