Project description:Genome-wide analysis of single nucleotide polymorphisms in 64 acute myeloid leukemias has revealed that 20% exhibited large regions of homozygosity that could not be accounted for by visible chromosomal abnormalities in the karyotype. Further analysis confirmed that these patterns were due to partial uniparental disomy (UPD). Remission bone marrow was available from five patients showing UPD in their leukemias, and in all cases the homozygosity was found to be restricted to the leukemic clone. Two examples of UPD11p were shown to be of different parental origin as indicated by the methylation pattern of the H19 gene. Furthermore, a previously identified homozygous mutation in the CEBPA gene coincided with a large-scale UPD on chromosome 19. These cryptic chromosomal abnormalities, which seem to be nonrandom, have the characteristics of somatic recombination events and may define an important new subclass of leukemia. Patient No. from Table 1 of Raghavan et al 2005 and Sample name; Patient No: 1 = Sample name: AML sample 35 diagnosis; Patient No: 1 = Sample name: AML sample 107 remission; Patient No: 2 = Sample name: AML sample 37 diagnosis; Patient No: 3 = Sample name: AML sample 10 diagnosis; Patient No: 3 = Sample name: AML sample 44 remission; Patient No: 4 = Sample name: AML sample 20 diagnosis; Patient No: 5 = Sample name: AML sample 65 diagnosis; Patient No: 6 = Sample name: AML sample 69 diagnosis; Patient No: 6 = Sample name: AML sample 94 remission; Patient No: 7 = Sample name: AML sample 40 diagnosis; Patient No: 7 = Sample name: AML sample 41 remission; Patient No: 8 = Sample name: AML sample 64 diagnosis; Patient No: 9 = Sample name: AML sample 7 diagnosis; Patient No: 10 = Sample name: AML sample 49 diagnosis; Patient No: 10 = Sample name: AML sample 106 remission; Patient No: 11 = Sample name: AML sample 76 diagnosis; Patient No: 12 = Sample name: AML sample 79 diagnosis Experiment Overall Design: DNA from 64 diagnostic AML samples were analysed using Affymetrix 10K SNP arrays. Large regions of homozygosity were identified and compared with remission bone marrow where available.
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: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: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. Experiment Overall Design: DNA from 27 pairs of diagnostic and relapsed AML samples were analysed using Affymetrix 10K SNP arrays. The genotype data of relapsed AML were compared with the data from the corresponding presentation 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:Genome-wide analysis of single nucleotide polymorphisms in 64 acute myeloid leukemias has revealed that 20% exhibited large regions of homozygosity that could not be accounted for by visible chromosomal abnormalities in the karyotype. Further analysis confirmed that these patterns were due to partial uniparental disomy (UPD). Remission bone marrow was available from five patients showing UPD in their leukemias, and in all cases the homozygosity was found to be restricted to the leukemic clone. Two examples of UPD11p were shown to be of different parental origin as indicated by the methylation pattern of the H19 gene. Furthermore, a previously identified homozygous mutation in the CEBPA gene coincided with a large-scale UPD on chromosome 19. These cryptic chromosomal abnormalities, which seem to be nonrandom, have the characteristics of somatic recombination events and may define an important new subclass of leukemia. Patient No. from Table 1 of Raghavan et al 2005 and Sample name Patient No: 1 = Sample name: AML sample 35 diagnosis Patient No: 1 = Sample name: AML sample 107 remission Patient No: 2 = Sample name: AML sample 37 diagnosis Patient No: 3 = Sample name: AML sample 10 diagnosis Patient No: 3 = Sample name: AML sample 44 remission Patient No: 4 = Sample name: AML sample 20 diagnosis Patient No: 5 = Sample name: AML sample 65 diagnosis Patient No: 6 = Sample name: AML sample 69 diagnosis Patient No: 6 = Sample name: AML sample 94 remission Patient No: 7 = Sample name: AML sample 40 diagnosis Patient No: 7 = Sample name: AML sample 41 remission Patient No: 8 = Sample name: AML sample 64 diagnosis Patient No: 9 = Sample name: AML sample 7 diagnosis Patient No: 10 = Sample name: AML sample 49 diagnosis Patient No: 10 = Sample name: AML sample 106 remission Patient No: 11 = Sample name: AML sample 76 diagnosis Patient No: 12 = Sample name: AML sample 79 diagnosis Keywords: DNA copy number, loss of heterozygosity
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. 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:CTCF ChIP-seq of 39 primary samples derived from human acute leukemias, namely AML, T-ALL and mixed myeloid/lymphoid leukemias with CpG Island Methylator Phenotype (CIMP). Due to patient confidentiality considerations, the raw data files for this dataset have been deposited to the EGA controlled-access archive under the accession numbers EGAS00001007094 (study); EGAD00001011059 (dataset).