title: Segmental uniparental disomy is a commonly acquired genetic event in relapsed acute myeloid leukemia.
abstract: Despite advances in the curative treatment of acute myeloid leukemia (AML), recurrence will occur in the majority of cases. At diagnosis, acquisition of segmental uniparental disomy (UPD) by mitotic recombination has been reported in 15% to 20% of AML cases, associated with homozygous mutations in the region of loss of heterozygosity. This study aimed to discover if clonal evolution from heterozygous to homozygous mutations by mitotic recombination provides a mechanism for relapse. DNA from 27 paired diagnostic and relapsed AML samples were analyzed using genotyping arrays. Newly acquired segmental UPDs were observed at relapse in 11 AML samples (40%). Six were segmental UPDs of chromosome 13q, which were shown to lead to a change from heterozygosity to homozygosity for internal tandem duplication mutation of FLT3 (FLT3 ITD). Three further AML samples had evidence of acquired segmental UPD of 13q in a subclone of the relapsed leukemia. One patient acquired segmental UPD of 19q that led to homozygosity for a CEBPA mutation 207C>T. Finally, a single patient with AML acquired segmental UPD of chromosome 4q, for which the candidate gene is unknown. We conclude that acquisition of segmental UPD and the resulting homozygous mutation is a common event associated with relapse of AML.
authors.affiliation: Medical Oncology Unit, Centre for Molecular Oncology, Institute of Cancer, Barts and the London School of Medicine and Dentistry, London, UK. manoj.raghavan@cancer.org.uk
authors.forename: Manoj
authors.initials: M
authors.lastname: Raghavan
authors.forename: Lan-Lan
authors.initials: LL
authors.lastname: Smith
authors.forename: Debra M
authors.initials: DM
authors.lastname: Lillington
authors.forename: Tracy
authors.initials: T
authors.lastname: Chaplin
authors.forename: Ioannis
authors.initials: I
authors.lastname: Kakkas
authors.forename: Gael
authors.initials: G
authors.lastname: Molloy
authors.forename: Claude
authors.initials: C
authors.lastname: Chelala
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Cazier
authors.forename: James D
authors.initials: JD
authors.lastname: Cavenagh
authors.forename: Jude
authors.initials: J
authors.lastname: Fitzgibbon
authors.forename: T Andrew
authors.initials: TA
authors.lastname: Lister
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Young
mesh_terms: D000328:Adult; D000368:Aged; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics; D002882:Chromosomes, Human, Pair 13; D002888:Chromosomes, Human, Pair 19; D002894:Chromosomes, Human, Pair 4; D002999:Clone Cells; D005260:Female; D005838:Genotype; D006720:Homozygote; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011995:Recombination, Genetic; D012008:Recurrence; D024182:Uniparental Disomy; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D051941:fms-Like Tyrosine Kinase 3