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 de novo AML-NK. In three centers whole-genome microarray analyses were performed to delineate robust and common expression signatures for molecular markers in AML-NK. All samples were obtained from untreated patients at the time of diagnosis. Cells used for microarray analysis were collected from the purified fraction of mononuclear cells after Ficoll density centrifugation (Dresden, n=78; Munich, n=97; Ulm, n=77). Each laboratory performed its routine diagnostic algorithms, including the characterization of molecular markers.
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.
Project description:Normal Karyotype acute myeloid leukemia (NK-AML) represents approximately 50% of all cases of AML which patients develop. Most AML cell lines are highly abnormal and therefore not good models for investigating NK-AML biology a novel AML cell line, CG-SH, was recently estabished and here we characterize the gene expression and mutations present through high-throughput sequencing of RNA and genomic DNA using a HiSeq 2000 The overall design of the experiment was to characterize, at single base pair resolution, all of the genetic defects present in a novel normal karyotype cell line, CG-SH
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:Normal Karyotype acute myeloid leukemia (NK-AML) represents approximately 50% of all cases of AML which patients develop. Most AML cell lines are highly abnormal and therefore not good models for investigating NK-AML biology a novel AML cell line, CG-SH, was recently estabished and here we characterize the gene expression and mutations present through high-throughput sequencing of RNA and genomic DNA using a HiSeq 2000
Project description:The pretreatment karyotype of leukemic blasts is currently the key determinant in therapy decision-making in acute myeloid leukemia (AML). However, approximately fifty percent of AML patients, often carrying a normal karyotype, are currently unclassifiable based these established methods. Gene expression profiling has proven to be valuable for risk stratification of AML. This is a repository of 662 adult AML cases characterized on gene expression microarrays and used for different studies investigating the mechanisms underlying leukemogenesis. Bone marrow aspirates or peripheral blood samples of three independent representative cohorts of de novo AML patients, comprising 277, 256 and 129 cases respectively, were collected at diagnosis. Gene expression profiling was performed on 662 adult AML patients who have been treated according to Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research (HOVON/SAKK) AML-04, -04A, -29, -32, -42, -42A, -43 and -92 protocols (available at http://www.hovon.nl). All patients provided written informed consent in accordance with the Declaration of Helsinki, and the study was approved by all participating institutional review boards. Blast cell purification and RNA isolation were performed as previously described (Valk et al., Prognostically Useful Gene-Expression Profiles in Acute Myeloid Leukemia, New England Journal of Medicine, 2004).
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:Among acute myeloid leukemias (AML) with normal karyotype (CN-AML), NPM1 and CEBPA mutations define WHO provisional entities accounting for ~60% of cases, but the remaining ~40% remains poorly characterized. By whole exome-sequencing (WES) of one CN-AML patient lacking mutations in NPM1, CEBPA, FLT3, MLL-PTD and IDH1, we newly identified a clonal somatic mutation in BCOR (BCL6 co-repressor), a gene located in chromosome X. Further analyses showed that BCOR mutations occurred in 11/262 (4.2%) CN-AML cases and represented a substantial fraction (14/82, 17.1%) of CN-AML patients showing the same genetic background as the index patient subjected to WES. BCOR somatic mutations were: i) disruptive events similar to germline BCOR mutations causing the oculo-cranio-facial-dental (OCFD) genetic syndrome; ii) associated with markedly decreased BCOR mRNA levels, absence of full-length BCOR and absent or low expression of a truncated BCOR protein; iii) almost mutually exclusive with NPM1 mutations and frequently associated with DNMT3A and RUNX1 mutations, pointing to a cooperation between these events. Finally, BCOR mutations correlated with poor outcome among a cohort of 160 CN-AML patients (28% versus 66% overall survival at 2 yrs, P=0.024). Our results implicate for the first time BCOR in the pathogenesis of CN-AML without NPM1 mutations. AML samples with normal karyotype were studied. Molecular analyses were performed for BCOR mutations. 12 BCOR wild-type cases and 12 BCOR mutated cases were hybridized to gene expression micro-arrays.
Project description:About 40% of patients with myelodysplastic syndromes (MDS) present with a normal karyotype and they are facing different courses of disease. To advance the biological understanding and find molecular prognostic markers we performed a high resolution oligonucleotide array study of 107 MDS patients (FAB) with a normal karyotype. Recurrent hidden deletions overlapping with known cytogenetic aberrations or sites of known tumor associated genes were identified in 4q24 (TET2, 2x), 5q31.2 (2x), 7q22.1 (3x) and 21q22.12 (RUNX1, 2x). One patient with a 7q22.1 had an additional 5q31.2 deletion of the AML/MDS region; the smallest deletion identified so far and includes the putative tumor suppressor (ts) genes EGR1 and CTNNA1. One TET2 deletion was homozygous and one heterozygous, with a missense mutation in the remaining allele, further supporting its role as ts gene. Besides these recurrent alterations, additional individual imbalances were found in 34 cases; in total 42/107 (39%) cases had genomic imbalances, deletions were more frequent than gains. These patients had an inferior survival as compared with the rest of the patients (P=0.002). This study emphasizes the heterogeneity of MDS but points to interesting genes which may have diagnostic and prognostic impact. Array CGH experiment, MDS tumor cells vs. control DNA. Total of 107 tumors.
Project description:AML with mutated NPM1 usually carries normal karyotype (NK) but it may harbor chromosomal aberrations whose significance remains unclear. We addressed this question in 631 AML patients with mutated/cytoplasmic NPM1. An abnormal karyotype (AK) was present in 93/631 cases (14.7%), the most frequent abnormalities being +8, +4, -Y, del(9q), +21. Chromosome aberrations in NPM1-mutated AML were similar to, but occurred less frequently than additional chromosome changes found in other AML with recurrent cytogenetic abnormalities according to WHO classification. Four of the 31 NPM1-mutated AML patients karyotyped at different time points had NK at diagnosis but AK at relapse: del(9q) (n=2), t(2;11) (n=1), inv(12) (n=1). NPM1-mutated AML with NK or AK showed overlapping morphological, immunophenotypic (CD34-negativity) and gene expression profile (downregulation of CD34 and upregulation of HOX genes). No difference in survival was observed among NPM1-mutated AML patients independently of whether they carried a normal or abnormal karyotype, the NPM1-mutated/FLT3-ITD negative cases showing the better prognosis. Findings in our patients point to chromosomal aberrations as secondary events, reinforce the concept that NPM1 mutation is a founder genetic lesion and indicate that NPM1-mutated AML should be clinically handled as one entity, irrespective of the karyotype.