Genomic Imbalances Are Confined to Non-Proliferating Cells in Paediatric Patients with Acute Myeloid Leukaemia and a Normal or Incomplete Karyotype

Leukaemia is often associated with genetic alterations such as translocations, amplifications and deletions, and recurrent chromosome abnormalities are used as markers of diagnostic and prognostic relevance. However, a proportion of acute myeloid leukaemia (AML) cases have an apparently normal karyotype despite comprehensive cytogenetic analysis. Based on conventional cytogenetic analysis of banded chromosomes, we selected a series of 23 paediatric patients with acute myeloid leukaemia and performed whole genome array comparative genome hybridization (aCGH) using DNA samples derived from the same patients. Imbalances involving large chromosomal regions or entire chromosomes were detected by aCGH in seven of the patients studied. Results were validated by fluorescence in situ hybridization (FISH) to both interphase nuclei and metaphase chromosomes using appropriate bacterial artificial chromosome (BAC) probes. The majority of these copy number alterations (CNAs) were confirmed by FISH and found to localize to the interphase rather than metaphase nuclei. Furthermore, the proliferative states of the cells analyzed by FISH were tested by immunofluorescence using an antibody against the proliferation marker pKi67. Interestingly, these experiments showed that, in the vast majority of cases, the changes appeared to be confined to interphase nuclei in a non-proliferative status.

[1]  Bob Löwenberg,et al.  Review Articles (434 articles) , 2008 .

[2]  S. Knuutila,et al.  Genetic changes including gene copy number alterations and their relation to prognosis in childhood acute myeloid leukemia , 2010, Leukemia & lymphoma.

[3]  J. Kitzman,et al.  Acquired copy number alterations in adult acute myeloid leukemia genomes , 2009, Proceedings of the National Academy of Sciences.

[4]  A. Kallioniemi.  CGH microarrays and cancer. , 2008, Current opinion in biotechnology.

[5]  C. Bloomfield,et al.  Clinical outcome of de novo acute myeloid leukaemia patients with normal cytogenetics is affected by molecular genetic alterations: a concise review , 2007, British journal of haematology.

[6]  P. N. Rao,et al.  Guidance for fluorescence in situ hybridization testing in hematologic disorders. , 2007, The Journal of molecular diagnostics : JMD.

[7]  S. Knuutila,et al.  Oligonucleotide array-CGH reveals cryptic gene copy number alterations in karyotypically normal acute myeloid leukemia , 2007, Leukemia.

[8]  Stefan Fröhling,et al.  Disclosure of candidate genes in acute myeloid leukemia with complex karyotypes using microarray-based molecular characterization. , 2006, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[9]  Gerhard Ehninger,et al.  Prevalence and prognostic impact of NPM1 mutations in 1485 adult patients with acute myeloid leukemia (AML). , 2006, Blood.

[10]  Å. Borg,et al.  High-resolution genome-wide array-based comparative genome hybridization reveals cryptic chromosome changes in AML and MDS cases with trisomy 8 as the sole cytogenetic aberration , 2006, Leukemia.

[11]  B. Falini,et al.  Nucleophosmin mutations in childhood acute myelogenous leukemia with normal karyotype. , 2005, Blood.

[12]  T. Liehr,et al.  Detection of cryptic chromosomal aberrations in the in vitro non-proliferating cells of acute myeloid leukemia. , 2005, International journal of oncology.

[13]  Åsa Hedman,et al.  SW-ARRAY: a dynamic programming solution for the identification of copy-number changes in genomic DNA using array comparative genome hybridization data , 2005, Nucleic acids research.

[14]  C. Bloomfield,et al.  Cytogenetics in acute leukemia. , 2004, Blood reviews.

[15]  S. Fröhling,et al.  CEBPA mutations in younger adults with acute myeloid leukemia and normal cytogenetics: prognostic relevance and analysis of cooperating mutations. , 2004, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[16]  Julia R Fielding,et al.  Hypothesis testing I: proportions. , 2003, Radiology.

[17]  Axel Benner,et al.  Prognostic significance of activating FLT3 mutations in younger adults (16 to 60 years) with acute myeloid leukemia and normal cytogenetics: a study of the AML Study Group Ulm. , 2002, Blood.

[18]  C. Bloomfield,et al.  Pretreatment cytogenetic abnormalities are predictive of induction success, cumulative incidence of relapse, and overall survival in adult patients with de novo acute myeloid leukemia: results from Cancer and Leukemia Group B (CALGB 8461). , 2002, Blood.

[19]  Han G Brunner,et al.  High-throughput analysis of subtelomeric chromosome rearrangements by use of array-based comparative genomic hybridization. , 2002, American journal of human genetics.

[20]  C. Bloomfield,et al.  Clinical importance of cytogenetics in acute myeloid leukaemia. , 2001, Best practice & research. Clinical haematology.

[21]  F. Behm,et al.  Chromosomal abnormalities in 478 children with acute myeloid leukemia: clinical characteristics and treatment outcome in a cooperative pediatric oncology group study-POG 8821. , 1999, Blood.

[22]  K Wheatley,et al.  The importance of diagnostic cytogenetics on outcome in AML: analysis of 1,612 patients entered into the MRC AML 10 trial. The Medical Research Council Adult and Children's Leukaemia Working Parties. , 1998, Blood.

[23]  I. Kill.  Localisation of the Ki-67 antigen within the nucleolus. Evidence for a fibrillarin-deficient region of the dense fibrillar component. , 1996, Journal of cell science.

[24]  J. Harbott,et al.  Double target in situ hybridization applied to the study of numerical aberrations in childhood acute lymphoblastic leukemia. , 1994, Cancer genetics and cytogenetics.

[25]  J. Rowley.  The cytogenetics of acute leukaemia. , 1978, Clinics in haematology.

[26]  L. Shaffer,et al.  Comprar ISCN 2009 - An International System for Human Cytogenetic Nomenclature | Marilyn L. Slovak | 9783805589857 | Karger AG , 2009 .

[27]  Gerhard Ehninger,et al.  Prevalence and prognostic impact of NPM 1 mutations in 1485 adult patients with acute myeloid leukemia ( AML ) , 2006 .

[28]  E. Thorland,et al.  Preclinical validation of fluorescence in situ hybridization assays for clinical practice , 2006, Genetics in Medicine.

[29]  P. Lichter,et al.  Association of pKi-67 with satellite DNA of the human genome in early G1 cells , 2004, Chromosome Research.

[30]  C. Felix,et al.  The molecular basis of leukemia. , 2004, Hematology. American Society of Hematology. Education Program.

[31]  J. Fantes.  Analyzing Chromosomes , 2004, Chromosome Research.

[32]  L. Kearney,et al.  Detection of chromosome abnormalities in leukemia using fluorescence in situ hybridization. , 2002, Methods in molecular medicine.

[33]  M. Slovak,et al.  Karyotypic analysis predicts outcome of preremission and postremission therapy in adult acute myeloid leukemia: a Southwest Oncology Group/Eastern Cooperative Oncology Group Study. , 2000, Blood.

[34]  O. Garson.  Cytogenetics in acute leukaemia , 1979 .

[35]  Iscn.  International System for Human Cytogenetic Nomenclature , 1978 .