Purpose: CEBPA mutations are found as either biallelic (biCEBPA) or monoallelic (moCEBPA). We set out to explore whether the kind of CEBPA mutation is of prognostic relevance in cytogenetically normal AML (CN-AML).
Acute myeloid leukemia with biallelic CEBPA gene mutations and normal karyotype represents a distinct genetic entity associated with a favorable clinical outcome.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Stem cell gene expression programs influence clinical outcome in human leukemia.
Specimen part
View SamplesExperiments using xenografts show that some solid tumours and leukemias are organized as cellular hierarchies sustained by cancer stem cells (CSC). Despite promise, the relevance of the CSC model to human disease remains uncertain. Here we show that acute myeloid leukemia (AML) follows a CSC model based on sorting multiple populations from each of 16 primary human AML samples and identifying which contain leukemia stem cells (LSC) using a sensitive xenograft assay. Analysis of gene expression from all functionally validated populations yielded an LSC-specific signature. Similarly, a hematopoietic stem cell (HSC) gene signature was established. Bioinformatic analysis identified a core transcriptional program shared by LSC and HSC, revealing the molecular machinery underlying stemness properties. Both stem cell programs were highly significant independent predictors of patient survival and also found in existing prognostic signatures. Thus, determinants of stemness influence clinical outcome of AML establishing that LSC are clinically relevant and not mere artifacts of xenotransplantation.
Stem cell gene expression programs influence clinical outcome in human leukemia.
No sample metadata fields
View SamplesMesenchymal stromal cells (MSC) are crucial components of the bone marrow (BM) microenvironment essential for regulating self-renewal, survival and differentiation of hematopoietic stem/progenitor cells (HSPC) in the stem cell niche. MSC are functionally and phenotypically altered in myelodysplastic syndromes (MDS), contributing to disease progression. MDS MSC do not harbor recurrent genetic alterations but have been shown to exhibit an altered methylome compared to MSC from healthy controls. We examined growth, differentiation and HSPC-supporting capacity of ex vivo expanded MSC from MDS patients in comparison to age-matched healthy controls after direct treatment in vitro with the hypomethylating agent azacitidine (AZA). We show that AZA exerts a direct effect on MSC by modulating their differentiation potential. Osteogenesis was significantly boosted in healthy MSC while adipogenesis was inhibited in both healthy and MDS MSC. In co-culture experiments, both AZA treated MDS MSC and healthy MSC exhibited enhanced support of non-clonal HSPC which was associated with increased cell cycle induction. Conversely, clonal MDS HSPC were inhibited by contact with AZA treated MSC. RNA-sequencing analyses of stromal cells revealed changes in pathways essential for HSPC support as well as in immune regulatory pathways. In sum, our data demonstrate that AZA treatment of stromal cells leads to upregulation of HSPC-supportive genes and cell cycle induction in co-cultured healthy HSPC, resulting in a proliferative advantage over clonal HSPC. Thus, restoration of functional hematopoiesis by AZA may be driven by activated stromal support factors in MSC providing cell cycle cues to healthy HSPC. Overall design: RNA sequencing was performed on a mesenchymal stromal cell line (EL08-1D2), either untreated or treated with Azacitidine [(-)AZA vs. (+)AZA].
Direct modulation of the bone marrow mesenchymal stromal cell compartment by azacitidine enhances healthy hematopoiesis.
Treatment, Subject
View SamplesExperiments using xenografts show that some solid tumours and leukemias are organized as cellular hierarchies sustained by cancer stem cells (CSC). Despite promise, the relevance of the CSC model to human disease remains uncertain. Here we show that acute myeloid leukemia (AML) follows a CSC model based on sorting multiple populations from each of 16 primary human AML samples and identifying which contain leukemia stem cells (LSC) using a sensitive xenograft assay. Analysis of gene expression from all functionally validated populations yielded an LSC-specific signature. Similarly, a hematopoietic stem cell (HSC) gene signature was established. Bioinformatic analysis identified a core transcriptional program shared by LSC and HSC, revealing the molecular machinery underlying stemness properties. Both stem cell programs were highly significant independent predictors of patient survival and also found in existing prognostic signatures. Thus, determinants of stemness influence clinical outcome of AML establishing that LSC are clinically relevant and not mere artifacts of xenotransplantation.
Stem cell gene expression programs influence clinical outcome in human leukemia.
Specimen part
View SamplesChronic lymphocytic leukemia (CLL) is a common and heterogeneous disease. An accurate prediction of outcome is highly relevant for the development of personalized treatment strategies. Microarray technology was shown to be a useful tool for the development of prognostic gene expression scores. However, there are no gene expression scores which are able to predict overall survival in CLL based on the expression of few genes that are better than established prognostic markers. We correlated 151 CLL microarray data sets with overall survival using Cox regression and supervised principal component analysis to derive a prognostic score. This score based on the expression levels of eight genes and was validated in an independent group of 149 CLL patients by quantitative real time PCR. The score was predictive for overall survival and time to treatment in univariate Cox regression in the validation data set (both: p<0.001) and in a multivariate analysis after adjustment for 17p and 11q deletions and the IgVH-status. The score achieved superior prognostic accuracy compared to models based on genomic aberrations and IgVH-status and may support personalized therapy.
An eight-gene expression signature for the prediction of survival and time to treatment in chronic lymphocytic leukemia.
Specimen part, Disease, Disease stage
View SamplesThe translocation t(10,11)(p13;q14) resulting in the formation of the CALM/AF10 fusion gene is involved in various hematological malignancies including acute myeloid leukemia, T-cell acute lymphoblastic leukemia, and malignant lymphoma and is usually associated with poor prognosis. We established a knock-in mouse model allowing tissue-specific CALM/AF10 expression from the Rosa26 locus using a loxP-STOP-loxP cassette to study leukemic transformation by the CALM/AF10 fusion protein during hematopoiesis. vav-Cre induced pan-hematopoietic expression of the CALM/AF10 fusion gene led to acute leukemia with a median latency of 12 months. Leukemias were either myeloid or had myeloid feature and showed expression of the B cell marker B220. Gene expression profiling of leukemic bone marrow cells revealed the overexpression of Hoxa cluster genes and the Hox co-factor Meis1. The long latency to leukemia development suggested that additional, collaborative genetic lesions are required. We identified an average of 2 to 3 additional mutations per leukemia using whole-exome sequencing. When CALM/AF10 was expressed in the B lymphoid compartment using mb1-Cre or CD19-Cre inducer lines no leukemia development was observed. Our results indicate that CALM/AF10 needs to be expressed from the stem or early progenitor cell stage onward to permit the acquisition of additional mutations required for leukemic transformation.
The target cell of transformation is distinct from the leukemia stem cell in murine CALM/AF10 leukemia models.
Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Adults with Philadelphia chromosome-like acute lymphoblastic leukemia frequently have IGH-CRLF2 and JAK2 mutations, persistence of minimal residual disease and poor prognosis.
Specimen part, Disease, Disease stage
View SamplesPhiladelphia-like B-cell precursor acute lymphoblastic leukemia (Ph-like ALL) is characterized by distinct genetic alterations and inferior prognosis in children and younger adults. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults. Among 207 adult B-cell precursor ALL patients, 26 (13%) were classified as Ph-like using Affymetrix microarrays. The incidence of this subtype was 25% among 105 B-cell precursor ALL patients negative for BCR-ABL1 and MLL-translocations (B-other). All patients with IgH-CRLF2 translocation (38% vs 0%; p=0.002) or mutations in JAK2 (44% vs. 0%; p<0.001) were exclusively found in the Ph-like subgroup. Clinical and outcome analyses were restricted to patients treated within GMALL trials 06/99 and 07/03 (n=107). The complete remission (CR) rate after induction was 100% for Ph-like (n=19) and B-other patients (n=40). After induction, significantly fewer Ph-like patients reached molecular CR (33% vs 79%; p=0.01). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous CR (24% vs 62%; p<0.001) and overall survival (22% vs 64%; p=0.006) compared to B-other ALL patients. Subsequent analysis led to a clinically applicable algorithm identifying this patient subset with a specificity of 100%. Our study is the first to demonstrate that the profile of genetic events in adult Ph-like ALL resembles pediatric Ph-like ALL and differs from B-other ALL. The Ph-like phenotype associates with inferior outcomes in intensively treated adult ALL patients. Ph-like adult ALL should be recognized as a distinct, high-risk entity and further research on improved diagnostic and therapeutic approaches is needed.
Adults with Philadelphia chromosome-like acute lymphoblastic leukemia frequently have IGH-CRLF2 and JAK2 mutations, persistence of minimal residual disease and poor prognosis.
Specimen part, Disease, Disease stage
View SamplesPhiladelphia-like B-cell precursor acute lymphoblastic leukemia (Ph-like ALL) is characterized by distinct genetic alterations and inferior prognosis in children and younger adults. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults. Among 207 adult B-cell precursor ALL patients, 26 (13%) were classified as Ph-like using Affymetrix microarrays. The incidence of this subtype was 25% among 105 B-cell precursor ALL patients negative for BCR-ABL1 and MLL-translocations (B-other). All patients with IgH-CRLF2 translocation (38% vs 0%; p=0.002) or mutations in JAK2 (44% vs. 0%; p<0.001) were exclusively found in the Ph-like subgroup. Clinical and outcome analyses were restricted to patients treated within GMALL trials 06/99 and 07/03 (n=107). The complete remission (CR) rate after induction was 100% for Ph-like (n=19) and B-other patients (n=40). After induction, significantly fewer Ph-like patients reached molecular CR (33% vs 79%; p=0.01). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous CR (24% vs 62%; p<0.001) and overall survival (22% vs 64%; p=0.006) compared to B-other ALL patients. Subsequent analysis led to a clinically applicable algorithm identifying this patient subset with a specificity of 100%. Our study is the first to demonstrate that the profile of genetic events in adult Ph-like ALL resembles pediatric Ph-like ALL and differs from B-other ALL. The Ph-like phenotype associates with inferior outcomes in intensively treated adult ALL patients. Ph-like adult ALL should be recognized as a distinct, high-risk entity and further research on improved diagnostic and therapeutic approaches is needed.
Adults with Philadelphia chromosome-like acute lymphoblastic leukemia frequently have IGH-CRLF2 and JAK2 mutations, persistence of minimal residual disease and poor prognosis.
Specimen part, Disease, Disease stage
View Samples