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:The acquisition of uniparental disomy (aUPD) in acute myeloid leukemia (AML) results in homozygosity for known gene mutations. Uncovering novel regions of aUPD has the potential to identify previously unknown mutational targets, therefore, we aimed to develop a comprehensive map of the regions of aUPD in AML. Here, we have analyzed a large set of diagnostic AML samples (n=455) using genotype arrays. Acquired UPD was found in 17% of the samples with a non-random distribution particularly affecting chromosomes 13q, 11p and 11q. Novel recurrent regions of aUPD were uncovered at 2p, 17p, 2q, 17q, 1p and Xq. Overall, aUPDs were observed across all cytogenetic risk groups, although samples with aUPD13q (5.4% of samples) belonged exclusively to the intermediate-risk group. All cases with a high FLT3-ITD level, measured previously, had aUPD13q covering the FLT3 gene. Of the 120 aUPDs observed, the majority (87%) were due to mitotic recombination while only 13% were due to non-disjunction. This study demonstrates aUPD is a frequent and significant finding in AML and pinpoints regions that may contain novel mutational targets. Experiment Overall Design: Genomic DNA from 459 diagnostic AML samples were analysed using Affymetrix 10K 2.0 SNP arrays. Genomic DNA from the blood of ten unrelated controls was used as reference for all 459 AML samples. Remission DNA from 8 AML samples was also studied. Prevalence and regions of homozygosity were identified.
Project description:The acquisition of uniparental disomy (aUPD) in acute myeloid leukemia (AML) results in homozygosity for known gene mutations. Uncovering novel regions of aUPD has the potential to identify previously unknown mutational targets, therefore, we aimed to develop a comprehensive map of the regions of aUPD in AML. Here, we have analyzed a large set of diagnostic AML samples (n=455) using genotype arrays. Acquired UPD was found in 17% of the samples with a non-random distribution particularly affecting chromosomes 13q, 11p and 11q. Novel recurrent regions of aUPD were uncovered at 2p, 17p, 2q, 17q, 1p and Xq. Overall, aUPDs were observed across all cytogenetic risk groups, although samples with aUPD13q (5.4% of samples) belonged exclusively to the intermediate-risk group. All cases with a high FLT3-ITD level, measured previously, had aUPD13q covering the FLT3 gene. Of the 120 aUPDs observed, the majority (87%) were due to mitotic recombination while only 13% were due to non-disjunction. This study demonstrates aUPD is a frequent and significant finding in AML and pinpoints regions that may contain novel mutational targets. Keywords: Genomic analysis of AML samples
Project description:Utilizing reciprocal genome-wide uniparental disomy samples presenting with Beckwith-Wiedemann and Silver-Russell syndrome-like phenotypes, we have analyzed ~0.1% of CpG dinucleotides present in the human genome for imprinted differentially methylated regions (DMRs) using the Illumina Infinium HumanMethylation27 BeadChip microarray. This approach identified 15 imprinted DMRs associated with previously characterized imprinted domains, and confirmed the maternal methylation of the RB1 DMR. In addition, we discovered two novel DMRs: a maternally methylated region overlapping the FAM50B promoter CpG island, which results in paternal expression of this retrotransposon, and a paternally methylated region located between maternally expressed ZNF597 and NAT15 genes. We analyzed reciprocal genome-wide uniparental disomy samples (one maternal UPD and three paternal UPD samples) and six different normal somatic tissues derived from the three germinal layers (lymphocytes, buccal cells, placenta, brain, muscle, and fat) .
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: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:Methylation profiles of chr12-16 were generated by meDIP and array hybridisation in 3 cases with maternal uniparental disomy of chromosome 15, and three cases of paternal uniparental disomy of chromosome 15. Comparison of these profiles reveals differentially methylated (imprinted) regions on chromosome 15.
Project description:Utilizing reciprocal genome-wide uniparental disomy samples presenting with Beckwith-Wiedemann and Silver-Russell syndrome-like phenotypes, we have analyzed ~0.1% of CpG dinucleotides present in the human genome for imprinted differentially methylated regions (DMRs) using the Illumina Infinium HumanMethylation27 BeadChip microarray. This approach identified 15 imprinted DMRs associated with previously characterized imprinted domains, and confirmed the maternal methylation of the RB1 DMR. In addition, we discovered two novel DMRs: a maternally methylated region overlapping the FAM50B promoter CpG island, which results in paternal expression of this retrotransposon, and a paternally methylated region located between maternally expressed ZNF597 and NAT15 genes.