Project description:Acute myeloid leukemia with normal karyotype (NK-AML) represents a cytogenetic grouping with intermediate prognosis but substantial molecular and clinical heterogeneity. Within this subgroup, presence of FLT3 (FMS-like tyrosine kinase 3) internal tandem duplication (ITD) mutation predicts less favorable outcome. The goal of our study was to discover gene-expression patterns correlated with FLT3-ITD mutation, and to evaluate the utility of a FLT3 signature for prognostication. The dataset comprises gene-expression profiles of 137 normal karyotype acute myeloid leukemia (NK-AML) specimens carried out using Stanford cDNA microarrays, to accompany the study of L Bullinger et al. For each array, Channel 2 represents Cy5-labeled NK-AML RNA, and Channel 1 Cy3-labeled universal reference RNA. Keywords: Logical Set
Project description:Acute myeloid leukemia with normal karyotype (NK-AML) represents a cytogenetic grouping with intermediate prognosis but substantial molecular and clinical heterogeneity. Within this subgroup, presence of FLT3 (FMS-like tyrosine kinase 3) internal tandem duplication (ITD) mutation predicts less favorable outcome. The goal of our study was to discover gene-expression patterns correlated with FLT3-ITD mutation, and to evaluate the utility of a FLT3 signature for prognostication. The dataset comprises gene-expression profiles of 137 normal karyotype acute myeloid leukemia (NK-AML) specimens carried out using Stanford cDNA microarrays, to accompany the study of L Bullinger et al. For each array, Channel 2 represents Cy5-labeled NK-AML RNA, and Channel 1 Cy3-labeled universal reference RNA. Keywords: Logical Set DNA microarrays were used to profile gene expression in a training set of 65 NK-AML cases. Supervised analysis was applied to build a gene expression-based predictor of FLT3-ITD mutation status. The predictor was then evaluated by classifying expression profiles from an independent test set of 72 NK-AML cases.
Project description:Approximately one third of acute myeloid leukemias (AMLs) are characterized by aberrant cytoplasmic localization of Nucleophosmin (NPMc+ AML), consequent to mutations in the NPM putative nucleolar localization signal. These events are mutually exclusive with the major AML-associated chromosomal rearrangements, and are frequently associated with normal karyotype, Fms-like tyrosine kinase (FLT3) mutations and multilineage involvement. We report the gene expression profiles of 78 de novo AMLs (72 with normal karyotype; 6 with non-major chromosomal abnormalities) that were characterized for the subcellular localization and mutation status of NPM. Unsupervised clustering clearly separated NPMc+ from NPMc- AMLs, regardless of the presence of FLT3 mutations or non-major chromosomal rearrangements, supporting the concept that NPMc+ AML represents a distinct entity. The molecular signature of NPMc+ AML includes up-regulation of several genes putatively involved in the maintenance of a stem cell phenotype, suggesting that NPMc+ AML may derive from a multipotent hematopoietic progenitor. 78 de novo AMLs, negative for AML-associated chromosomal translocations at the cytogenetic and/or molecular level.
Project description:Approximately one third of acute myeloid leukemias (AMLs) are characterized by aberrant cytoplasmic localization of Nucleophosmin (NPMc+ AML), consequent to mutations in the NPM putative nucleolar localization signal. These events are mutually exclusive with the major AML-associated chromosomal rearrangements, and are frequently associated with normal karyotype, Fms-like tyrosine kinase (FLT3) mutations and multilineage involvement. We report the gene expression profiles of 78 de novo AMLs (72 with normal karyotype; 6 with non-major chromosomal abnormalities) that were characterized for the subcellular localization and mutation status of NPM. Unsupervised clustering clearly separated NPMc+ from NPMc- AMLs, regardless of the presence of FLT3 mutations or non-major chromosomal rearrangements, supporting the concept that NPMc+ AML represents a distinct entity. The molecular signature of NPMc+ AML includes up-regulation of several genes putatively involved in the maintenance of a stem cell phenotype, suggesting that NPMc+ AML may derive from a multipotent hematopoietic progenitor.
Project description:More than 40% of patients with AML have a normal karyotype and are included in the intermediate prognostic group, in which risk classification is currently poor defined and more molecular markers are needed to achieve treatment stratification. EVI1 overexpression (OE) has been reported to discriminate in this group those with a worse prognosis. The EVI1 mice homolog has a role in the HSC proliferation through Gata2 expression, therefore, GATA2, a transcription factor with a relevant role in hematopoiesis, could be a candidate gene in the leukemogenic transformation in AML in patients with normal karyotype, and in other subgroups. GATA2 OE was detected in 46% of cases with normal karyotype, and was more frequent among samples with FLT3-ITD (p=0.0021), especially among the AML-M1 cases. We found a mutational pattern FLT3-ITD/GATA2-OE/WT1-OE that could define a subgroup of patients with normal karyotype and AML-M1, with a different gene expression array pattern and a poor prognosis. Our results show that GATA2 OE is a common event in AML cases with normal karyotype (46%). The deregulation of the expression of the GATA2 transcription factor would lead to a hematopoietic differentiation impairs, focusing GATA2 as a candidate gene that fits in the cooperating model for the multistep pathogenesis that causes AML transformation. Keywords: Disease state analysis
Project description:10 to 30% normal karyotype acute myeloid leukemia (AML) patients express mutations in regulators of DNA methylation such as TET2 or DNMT3A in conjunction with activating mutation in receptor tyrosine kinase, FLT3, which can be present in up to 50% of normal karyotype AML patients. These patients have poor prognosis since they do not respond well to established therapies. Here, utilizing mouse models of AML that recapitulate cardinal features of the human disease and bear a combination of loss of function mutations in either Tet2 or Dnmt3a along with expression of Flt3ITD, we show that inhibition of SHP2, a protein tyrosine phosphatase, essential for cytokine receptor signaling, including FLT3, by a small molecule allosteric inhibitor, SHP099, impairs growth and induces differentiation of leukemic cells without impacting normal hematopoietic cells. We further show that SHP099 normalizes gene expression program associated with increased cell proliferation and self-renewal in leukemic cells by down regulating the Myc signature. Our results provide a new and more effective target for treating a subset of AML patients bearing a combination of genetic and epigenetic mutations.
Project description:Acute myeloid leukemia (AML) is a heterogeneous disease and AML with normal karyotype (AML-NK) is categorized as an intermediate-risk group. Over the past years molecular analyses successfully identified biomarkers that will further allow to dissecting clinically meaningful subgroups in this disease. Thus far, somatic mutations were identified which elucidate the disturbance of cellular growth, proliferation, and differentiation processes in hematopoietic progenitor cells. In AML-NK, acquired gene mutations with prognostic relevance were identified for FLT3, CEBPA, and NPM1. FLT3-ITD mutations were associated with short relapse-free and overall survival, while mutations in CEBPA or NPM1 (without concomitant FLT3-ITD) had a more favorable outcome. Here, we present a multicenter study investigating gene expression profiles of 251 cases of AML-NK. In three centers whole-genome microarray analyses were performed to delineate robust and common expression signatures for molecular markers in AML-NK.