Project description:Identification of Acquired Copy Number Alterations and Uniparental Disomies in Cytogenetically Normal Acute Myeloid Leukemia Using High-Resolution Single Nucleotide Polymorphism Analysis Recent advances in genome-wide single nucleotide polymorphism (SNP) analyses have revealed previously unrecognized microdeletions and uniparental disomy (UPD) in a broad spectrum of human cancers. As acute myeloid leukemia (AML) represents a genetically heterogeneous disease, this technology might prove helpful especially for cytogenetically normal AML (CN-AML) cases. Thus, we performed high-resolution SNP analyses in 157 adult cases of CN-AML. Regions of acquired UPD were identified in 12% of cases and most frequently affected chromosomes 6p, 11p, and 13q. Notably, acquired UPD was invariably associated with mutations in NPM1 or CEBPA that impair hematopoietic differentiation (P=0.008), suggesting that UPDs may preferentially target genes that are essential for proliferation and survival of hematopoietic progenitors. Acquired copy number alterations (CNAs) were detected in 49% of cases with losses found in two or more cases affecting e.g. chromosome bands 3p13-p14.1 and 12p13. Furthermore, we identified two cases with a cryptic t(6;11) as well as several non-recurrent aberrations pointing to leukemia relevant regions. With regard to clinical outcome, there appeared to be an association between UPD 11p and UPD 13q cases with overall survival. These data demonstrate the potential of high-resolution SNP analysis for identifying genomic regions of potential pathogenic and clinical relevance in AML.
Project description:With the whole genome SNP array information obtained from tumor and matched normal control, we could evaluate the acquired copy number alterations (CNAs) and uniparental disomies (UPDs) . Here we identified somatic mutations by whole-exome sequencing in 25 NKTCL patients and extended validation through targeted sequencing in an additional 80 cases.
Project description:Relapse is the commonest cause of death in acute myeloid leukaemia (AML), but the mechanisms leading to relapse are unclear. Recently, acquisition of segmental uniparental disomy (UPD) by mitotic recombination (MR) has been reported in 15-20% of AML samples at diagnosis using whole genome single nucleotide polymorphism (SNP) arrays. These cytogenetically invisible abnormalities are associated with homozygous mutations in several types of malignancy. Clonal evolution of heterozygous to homozygous mutations by MR could provide a mechanism for relapse. Keywords: DNA copy number, loss of heterozygosity
Project description:With the whole genome SNP array information obtained from tumor and matched normal control, we could evaluate the acquired copy number variations (CNVs) and uniparental disomies (UPDs) . Seven MDS patients in a whole genome sequencing project were included in this experiment.
Project description:In order to examine if acquired copy number alterations in DNA repair genes is commonly observed in therapy-related AML, we used this custom built NimbleGen array with dense tiling of probes in 170 DNA repair genes to interrogate paired normal (skin) and tumor (bone marrow) samples.
Project description:Copy number analysis was performed using genotyping microarrays for 20 choroid plexus tumors. Genomic aberrations were investigated by tumor histological classification and the pattern observed in each subgroup was further refined. Allele-specific copy number analysis also allowed us to identify regions of acquired uniparental disomy with neutral copy number values.
Project description:Copy number analysis was performed using genotyping microarrays for 55 choroid plexus tumors. Genomic aberrations were investigated by tumor histological classification and the pattern observed in each subgroup was further refined. Allele specific copy number analysis also allowed us to identify regions of acquired uniparental disomy with neutral copy number values.
Project description:<p>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.</p> <p>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.</p> <p>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.</p> <p>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>.</p>
Project description:With the whole genome SNP array information obtained from tumor and matched normal control, we could evaluate the acquired copy number variations (CNVs) and uniparental disomies (UPDs) . Seven MDS patients in a whole genome sequencing project were included in this experiment. To detect acquired CNVs and UPDs in MDS patients, we genotyped both CD34+ cell from bone marrow and matched skin tissue.