title: Rapid intraclonal switch of lineage dominance in congenital leukaemia with a MLL gene rearrangement.
abstract: We describe a case of neonatal mixed lineage leukaemia which presented with a dominant B progenitor lymphoblast population plus a minor monocytic component. Treatment of the patient with corticosteroid and Ara-C resulted in loss of lymphoblasts and a rapid (within 7 days) increase and dominance of the monocytic component. The common clonal origin of the two cell types was evident from the identical rearrangement in the MLL gene and a shared rearrangement of one IGH allele. In common with other neonatal or infant ALL with MLL gene rearrangements, this leukaemia may have originated in a common B-monocytic lineage stem cell during foetal haemopoiesis. The observations further suggest that the therapeutic impact of the MLL gene rearrangement is to some extent dependent on the cellular context in which it is expressed.
authors.affiliation: Leukaemia Research Fund Centre, Institute of Cancer Research, London, UK.
authors.forename: S A
authors.initials: SA
authors.lastname: Ridge
authors.forename: M E
authors.initials: ME
authors.lastname: Cabrera
authors.forename: A M
authors.initials: AM
authors.lastname: Ford
authors.forename: S
authors.initials: S
authors.lastname: Tapia
authors.forename: C
authors.initials: C
authors.lastname: Risueño
authors.forename: S
authors.initials: S
authors.lastname: Labra
authors.forename: F
authors.initials: F
authors.lastname: Barriga
authors.forename: M F
authors.initials: MF
authors.lastname: Greaves
mesh_terms: D004268:DNA-Binding Proteins / Q000235:genetics*; D015321:Gene Rearrangement; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D007231:Infant, Newborn; D007938:Leukemia / Q000151:congenital / Q000235:genetics* / Q000378:metabolism; D008297:Male; D051788:Myeloid-Lymphoid Leukemia Protein; D011519:Proto-Oncogenes; D014157:Transcription Factors
chemical_list: D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase