Dataset Information

Acquired Copy Number Alterations in Adult Acute Myeloid Leukemia Genomes

ABSTRACT:

We performed genome-wide copy number analysis with paired normal and tumor DNA obtained from 86 adult patients with de novo AML using the Affymetrix Genome-Wide Human SNP array 6.0 containing 1.85 million features. Acquired copy number alterations (CNA) were confirmed using an independent, higher resolution, custom array comparative genomic hybridization platform.

A total of 201 somatic CNA were found in the 86 AML genomes (mean 2.34 CNA/genome), with FAB M6 and M7 AML genomes containing the most changes (10-29 CNA/genome). Twenty-four percent of AML patients with normal cytogenetics had CNA, while 40% of patients with an abnormal karyotype had additional CNA detected by SNP array, and several regions contained CNA in multiple AML genomes. The mRNA expression levels of 57 genes were significantly altered in 27 of 50 recurrent CNA regions <5 megabases in size. Array data are available online at http://www.ncbi.nlm.nih.gov/geo/ as GEO accession #GSE10358. A total of 8 uniparental disomy (UPD) segments were identified in the 86 genomes and 6/8 UPD regions occurred in samples with a normal karyotype. Collectively, 40% of AML genomes contained alterations not found with cytogenetics, and 96% of these regions contained known or novel AML associated genes. 43/86 AML genomes had no CNA or UPD at this level of resolution. The number of CNA per genome was not associated with overall survival, independent of cytogenetic classification.

In this study of 86 adult AML genomes, subcytogenetic CNAs or UPD did not add prognostic information to standard cytogenetics. However, arrays identified many somatically mutated oncogenes and tumor suppressor genes, and also genes not previously implicated in AML that may be relevant for pathogenesis.

AML CNA segments from 86 adult AML patients are available through dbVar at ftp://ftp.ncbi.nlm.nih.gov/pub/dbVar/data/Homo_sapiens/nstd11_Walter_et_al_2009.

PROVIDER: phs000201.v1.p1 | EGA |

REPOSITORIES: EGA

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Publications

DNA sequencing of a cytogenetically normal acute myeloid leukaemia genome.

Ley Timothy J TJ Mardis Elaine R ER Ding Li L Fulton Bob B McLellan Michael D MD Chen Ken K Dooling David D Dunford-Shore Brian H BH McGrath Sean S Hickenbotham Matthew M Cook Lisa L Abbott Rachel R Larson David E DE Koboldt Dan C DC Pohl Craig C Smith Scott S Hawkins Amy A Abbott Scott S Locke Devin D Hillier Ladeana W LW Miner Tracie T Fulton Lucinda L Magrini Vincent V Wylie Todd T Glasscock Jarret J Conyers Joshua J Sander Nathan N Shi Xiaoqi X Osborne John R JR Minx Patrick P Gordon David D Chinwalla Asif A Zhao Yu Y Ries Rhonda E RE Payton Jacqueline E JE Westervelt Peter P Tomasson Michael H MH Watson Mark M Baty Jack J Ivanovich Jennifer J Heath Sharon S Shannon William D WD Nagarajan Rakesh R Walter Matthew J MJ Link Daniel C DC Graubert Timothy A TA DiPersio John F JF Wilson Richard K RK

Nature 20081101 7218

Acute myeloid leukaemia is a highly malignant haematopoietic tumour that affects about 13,000 adults in the United States each year. The treatment of this disease has changed little in the past two decades, because most of the genetic events that initiate the disease remain undiscovered. Whole-genome sequencing is now possible at a reasonable cost and timeframe to use this approach for the unbiased discovery of tumour-specific somatic mutations that alter the protein-coding genes. Here we presen ...[more]

PMID: 18987736

Publication: 1/3

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Project description:We performed genome-wide copy number analysis with paired normal and tumor DNA obtained from 86 adult patients with de novo AML using the Affymetrix Genome-Wide Human SNP array 6.0 containing 1.85 million features. Acquired copy number alterations (CNA) were confirmed using an independent, higher resolution, custom array comparative genomic hybridization platform. A total of 201 somatic CNA were found in the 86 AML genomes (mean 2.34 CNA/genome), with FAB M6 and M7 AML genomes containing the most changes (10-29 CNA/genome). Twenty-four percent of AML patients with normal cytogenetics had CNA, while 40% of patients with an abnormal karyotype had additional CNA detected by SNP array, and several regions contained CNA in multiple AML genomes. The mRNA expression levels of 57 genes were significantly altered in 27 of 50 recurrent CNA regions <5 megabases in size. Array data are available online at <a href="http://www.ncbi.nlm.nih.gov/geo/" target="_blank">http://www.ncbi.nlm.nih.gov/geo/</a> as GEO accession #GSE10358. A total of 8 uniparental disomy (UPD) segments were identified in the 86 genomes and 6/8 UPD regions occurred in samples with a normal karyotype. Collectively, 40% of AML genomes contained alterations not found with cytogenetics, and 96% of these regions contained known or novel AML associated genes. 43/86 AML genomes had no CNA or UPD at this level of resolution. The number of CNA per genome was not associated with overall survival, independent of cytogenetic classification. In this study of 86 adult AML genomes, subcytogenetic CNAs or UPD did not add prognostic information to standard cytogenetics. However, arrays identified many somatically mutated oncogenes and tumor suppressor genes, and also genes not previously implicated in AML that may be relevant for pathogenesis. AML CNA segments from 86 adult AML patients are available through dbVar at <a href="ftp://ftp.ncbi.nlm.nih.gov/pub/dbVar/data/Homo_sapiens/nstd11_Walter_et_al_2009">ftp://ftp.ncbi.nlm.nih.gov/pub/dbVar/data/Homo_sapiens/nstd11_Walter_et_al_2009</a>.

Project description:We analysed, by last-generation high-resolution SNP arrays, Normal Karyotype (NK)-AML patients at diagnosis (Dx) and remission (R) phases, in order to determine the number of tumor-associated copy number abnormalities (CNAs) and copy neutral-loss of heterozygosity (CN-LOH) regions per patient and to identify possible recurring genomic abnormalities. The number of tumor-associated CNAs was detemined after comparison of 11 matched Dx/R samples using stringent conditions able to reduce the number of false positive CNAs. 8 additional unmatched Dx samples were included in the analysis of recurring CNAs and for detection of broad CN-LOH segments. With the exception of a single outlier case, a low number of CNAs per patient was detected (median value of 1 somatic loss or gain per patient). However, a high prevalence of CNAs (60-70% of the patients showed at least 1 tumor-associated gain or loss) and few recurring CNAs were observed, thus providing new hints towards identification of cooperating mutations. An extensive search of all CN-LOH regions > 1 Mb revealed only 3 broad regions (terminal 12Mb of 22q, terminal 27Mb of 1p and the whole chromosome 21) in three patients out of 19 (16%). CN-LOH of the whole chromosome 21 was responsible for homozygosity of a missense mutation (R80C) of RUNX1/AML1. Our study suggests that a relative submicroscopic copy number stability NK-AML genomes is associated with low recurrence of specific CNAs and CN-LOH in NK-AML patient population. Nineteen AML bone marrow samples were collected at the time of diagnosis (>90% blasts), defined as karyotypically-normal on the basis of standard metaphase cytogenetics (MC) and analysed by the Affymetrix SNP 6.0 arrays. In 11 of such cases (matched Dx) we obtained a bone marrow sample at the remission phase (matched R) of comparable high quality as evaluated by Contrast QC and MAPD values. In 8 cases (unmatched Dx) the corresponding R sample was not available or was not of comparable quality. As a reference set the publicly available data from 270 HapMap individuals were used.

Project description:Full Title: Multilineage Dysplasia (MLD) in AML correlates with MDS-related cytogenetic abnormalities and a prior history of MDS or MDS/MPN but has no independent prognostic relevance: A comparison of 408 cases classified as “AML not otherwise specified” or “AML with myelodysplasia-related changes” The WHO classification of acute myeloid leukemia (AML) is hierarchically structured and integrates genetic information, data on patients’ history, and multilineage dysplasia (MLD). The category “AML with MDS-related changes” (AML-MRC) is separated from AML not otherwise specified (AML-NOS) by the presence of either MLD, MDS-related cytogenetics or MDS history. To clarify whether MLD alone is clinically relevant, we analyzed 408 adult patients categorized as AML-MRC or AML-NOS. EFS (Median 13.8 months vs. 16.0 months) and 3-year-OS (45.8% vs. 53.9%) did not differ significantly between patients with MLD and without. However, MLD correlated with pre-existing MDS (p<0.001) and MDS-related cytogenetics (p=0.035). Patients with MLD as sole AML-MRC criterion (AML-MLD-sole; n=90) had less frequently FLT3-ITD (p=0.032), and a lower median age than AML-NOS (n=232), but EFS, OS, and WBC did not differ significantly. Contrarily, patients with AML-NOS plus AML-MLD-sole (n=323) versus patients with MDS history or MDS-related cytogenetics (n=85) had better EFS (16.9 vs. 10.7 months; p=0.005) and 3-year-OS (55.8% vs. 32.5%; p=0.001). Gene expression profiles were measured for a subset of 96 patients. Analysis of the expression data showed distinct clusters for AML-MLD-sole and AML-NOS versus AML with MDS-related cytogenetics or MDS history. Thus, MLD demonstrated no independent clinical impact, while cytogenetics and MDS history were of prognostic relevance. This data suggest modifications in a revised WHO proposal. All 96 bone marrow samples were obtained from untreated patients at the time of diagnosis. Cells used for microarray analysis were collected from the purified fraction of mononuclear cells after Ficoll density centrifugation.

Dataset Information

Acquired Copy Number Alterations in Adult Acute Myeloid Leukemia Genomes

Publications

DNA sequencing of a cytogenetically normal acute myeloid leukaemia genome.

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