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:Purpose: Genomic aberrations are of dominant importance to the biology and clinical outcome of patients with acute myelogenous leukemia (AML), and conventional karyotyping-based risk classifications are routinely used in clinical decision making in AML. One of the known limitations of karyotyping is the low sensitivity of this method to detect genomic abnormalities in the sub-megabase (Mb) to ~5 Mb range, and it is currently unclear whether overcoming this limitation with array-based high-resolution karyotyping could be clinically relevant. Furthermore, given the heterogeneity of molecular mechanisms/aberrations that underlie the risks inherent in conventional karyotyping-based risk classifications, it is likely that further refinements in genomic risk prognostication can be achieved. Here, we have analyzed FACS-sorted AML blast-derived and paired buccal DNA from 114 previously untreated prospectively enrolled AML patients for acquired genomic copy number changes and LOH using Affymetrix SNP 6.0 arrays, and we have correlated genomic lesion load and specific chromosomal abnormalities with patient survival. Conclusions: Using multivariate analyses, we found that having ≥2 genomic lesions detected through SNP 6.0 array profiling approximately doubles the risk of death when controlling for age and karyotype-based risk. Finally, we identified an independent negative prognostic impact of p53 mutations, 17p-LOH or both on survival in AML.
Project description:Recurrent gene mutations, chromosomal translocations, acquired genomic copy number aberrations (aCNA) and copy-neutral loss-of-heterozygosity (cnLOH) underlie the genomic pathogenesis of acute myelogenous leukemia (AML). Genomic lesion types from all of these categories have been variously associated with AML patient outcome. However, the patterns of co-occurrence of such lesions are only now beginning to be defined, and we seek to further delineate the relative influence of different types of genomic alterations on clinical outcomes in AML. In this study, we performed SNP 6.0 array-based genomic profiling of aCNA/cnLOH along with sequence analysis of 13 recurrently mutated genes on purified leukemic blast DNA from 156 prospectively enrolled non-FAB-M3 AML patients across the clinical spectrum of de novo, secondary, and therapy-related AML. We identify positive and negative associations of gene mutations, specific aCNA/cnLOH or total aCNA/cnLOH counts with different AML types as well as the associations of specific mutations with overall genomic complexity or genomic stability. Further, we show that NPM1, RUNX1, ASXL1 and TP53 mutations, elevated SNP-A-based genomic complexity, and specific recurrent aCNAs predict response to induction chemotherapy. Finally, results of comprehensive multivariate analyses support a dominant role for TP53 mutations or elevated genomic complexity as predictors of short survival in AML. Integrated genomic profiling of a clinically relevant adult AML population reveals the interplay between gene mutations, recurrent aCNAs, and SNP-A-based genomic complexity and identifies among them the genomic characteristics most associated with types of response to intensive induction therapies and with shortened overall survival.
Project description:Recurrent gene mutations, chromosomal translocations, acquired genomic copy number aberrations (aCNA) and copy-neutral loss-of-heterozygosity (cnLOH) underlie the genomic pathogenesis of acute myelogenous leukemia (AML). Genomic lesion types from all of these categories have been variously associated with AML patient outcome. However, the patterns of co-occurrence of such lesions are only now beginning to be defined, and we seek to further delineate the relative influence of different types of genomic alterations on clinical outcomes in AML. In this study, we performed SNP 6.0 array-based genomic profiling of aCNA/cnLOH along with sequence analysis of 13 recurrently mutated genes on purified leukemic blast DNA from 156 prospectively enrolled non-FAB-M3 AML patients across the clinical spectrum of de novo, secondary, and therapy-related AML. We identify positive and negative associations of gene mutations, specific aCNA/cnLOH or total aCNA/cnLOH counts with different AML types as well as the associations of specific mutations with overall genomic complexity or genomic stability. Further, we show that NPM1, RUNX1, ASXL1 and TP53 mutations, elevated SNP-A-based genomic complexity, and specific recurrent aCNAs predict response to induction chemotherapy. Finally, results of comprehensive multivariate analyses support a dominant role for TP53 mutations or elevated genomic complexity as predictors of short survival in AML. Integrated genomic profiling of a clinically relevant adult AML population reveals the interplay between gene mutations, recurrent aCNAs, and SNP-A-based genomic complexity and identifies among them the genomic characteristics most associated with types of response to intensive induction therapies and with shortened overall survival. This study is based on 156 patients with previously untreated AML for which paired tumor and normal samples were available. The patients were enrolled into this study at the University of Michigan Comprehensive Cancer Center. The study was approved by the University of Michigan Institutional Review Board (IRBMED #2004-1022) and written informed consent was obtained from all patients prior to enrollment. Genomic DNA was extracted from purified AML blasts and paired buccal cells. DNA thus obtained was hybridized to Affymetrix SNP 6.0 arrays.
Project description:Large but not small copy-number alterations correlate to high-risk genomic aberrations and survival in chronic lymphocytic leukemia: a high-resolution genomic screening of newly diagnosed patients. Single nucleotide polymorphism (SNP)-arrays allow simultaneous detection of copy-number aberrations (CNAs) and copy-number neutral loss-of-heterozygosity (CNN-LOH). In this study we investigated the presence of CNAs and CNN-LOH in newly diagnosed CLL samples from a Swedish chronic lymphocytic leukemia (CLL) cohort. In this study we could detect the known recurrent aberrations in CLL (i.e. deletions of 13q, 11q, 17p and trisomy 12). We also detected other both large and small CNAs which were mostly non-recurrent. CNN-LOH was detected on chromosome 13q in patients that carried homozygous deletion of 13q.