Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0023418 (leukemia)
93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Despite advances in the curative treatment of acute myeloid leukemia (AML), recurrence will occur in the majority of cases. At diagnosis, acquisition of segmental uniparental disomy (UPD) by mitotic recombination has been reported in 15% to 20% of AML cases, associated with homozygous mutations in the region of loss of heterozygosity. This study aimed to discover if clonal evolution from heterozygous to homozygous mutations by mitotic recombination provides a mechanism for relapse. DNA from 27 paired diagnostic and relapsed AML samples were analyzed using genotyping arrays. Newly acquired segmental UPDs were observed at relapse in 11 AML samples (40%). Six were segmental UPDs of chromosome 13q, which were shown to lead to a change from heterozygosity to homozygosity for internal tandem duplication mutation of FLT3 (FLT3 ITD). Three further AML samples had evidence of acquired segmental UPD of 13q in a subclone of the relapsed leukemia. One patient acquired segmental UPD of 19q that led to homozygosity for a CEBPA mutation 207C>T. Finally, a single patient with AML acquired segmental UPD of chromosome 4q, for which the candidate gene is unknown. We conclude that acquisition of segmental UPD and the resulting homozygous mutation is a common event associated with relapse of AML.
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PMID:Segmental uniparental disomy is a commonly acquired genetic event in relapsed acute myeloid leukemia. 1849 May 17

Acute myeloid leukemia (AML) represents a heterogeneous group of leukemia entities that differ with regard to biology, clinical course, and prognosis. Over the past decades, it has been shown that most AML cases exhibit chromosomal aberrations, gene mutations, and disordered gene expression that alter normal gene function, thereby contributing to leukemic transformation. Especially, in cytogenetically normal AML (CN-AML) molecular genetic and gene expression analyses are becoming of increasing importance. In addition to the impact of gene mutations, including the MLL, FLT3, CEBPA, or NPM1 genes in CN-AML, recent analyses have provided evidence that altered gene expression might not only be of biological but also of prognostic relevance in CN-AML patients. Quantitative reverse-transcriptase polymerase chain reaction (Q-RT-PCR) and recent advances in genome-wide DNA microarray-based gene expression profiling (GEP) represent powerful tools for the systematic exploration of the molecular variation underlying the biologic and clinical heterogeneity of CN-AML. Ultimately, a better understanding of gene expression alterations and hence the molecular basis of the disease will contribute to a refined leukemia classification, which will include both previously known CN-AML subgroups and novel classes defined by distinct gene expression clusters with prognostic significance.
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PMID:Gene expression with prognostic implications in cytogenetically normal acute myeloid leukemia. 1869 86

Owing to the heterogeneity of AML, the indication for allogeneic SCT (allo-SCT) requires an exact definition of the individual subentity and risk category. A comprehensive diagnostic approach is needed, which combines cytomorphology, cytogenetics, FISH, molecular genetics and immunophenotyping. Whereas the categorization in three prognostic karyotype groups is well established, rare recurrent aberrations as the unfavorable t(8;16)(p11;p13), inv(3)(q21q26) and t(6;9)(p23;q34) must also be considered. In normal karyotype, PCR analyses reveal prognostically relevant mutations in >85% of cases, and a molecular data set composed of the FLT3-ITD, MLL-PTD, NPM1 and CEBPA mutations was found able to guide the selection of patients for allo-SCT. Some novel markers as the WT1 mutations might further contribute to risk stratification in normal karyotype. The panel of minimal residual disease parameters is being expanded at this time, for example, by quantitative PCR for the NPM1 mutations. Immunophenotyping allows the definition of leukemia-associated phenotypes in nearly all cases, but its position in the indication to allo-SCT has to be validated. Thus, the optimization of the indication to allo-SCT is an ongoing process that should remain in continuous interaction with the increasing panel of known genetic markers and diagnostic methods.
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PMID:Interactive diagnostics in the indication to allogeneic SCT in AML. 1936 29

PURPOSE To determine the prognostic importance of the meningioma 1 (MN1) gene expression levels in the context of other predictive molecular markers, and to derive MN1 associated gene- and microRNA-expression profiles in cytogenetically normal acute myeloid leukemia (CN-AML). PATIENTS AND METHODS MN1 expression was measured in 119 untreated primary CN-AML adults younger than 60 years by real-time reverse-transcriptase polymerase chain reaction. Patients were also tested for FLT3, NPM1, CEBPA, and WT1 mutations, MLL partial tandem duplications, and BAALC and ERG expression. Gene- and microRNA-expression profiles were attained by performing genome-wide microarray assays. Patients were intensively treated on two first-line Cancer and Leukemia Group B clinical trials. Results Higher MN1 expression associated with NPM1 wild-type (P < .001), increased BAALC expression (P = .004), and less extramedullary involvement (P = .01). In multivariable analyses, higher MN1 expression associated with a lower complete remission rate (P = .005) after adjustment for WBC; shorter disease-free survival (P = .01) after adjustment for WT1 mutations, FLT3 internal tandem duplications (FLT3-ITD), and high ERG expression; and shorter survival (P = .04) after adjustment for WT1 and NPM1 mutations, FLT3-ITD, and WBC. Gene- and microRNA-expression profiles suggested that high MN1 expressers share features with high BAALC expressers and patients with wild-type NPM1. Higher MN1 expression also appears to be associated with genes and microRNAs that are active in aberrant macrophage/monocytoid function and differentiation. CONCLUSION MN1 expression independently predicts outcome in CN-AML patients. The MN1 gene- and microRNA-expression signatures suggest biologic features that could be exploited as therapeutic targets.
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PMID:Prognostic importance of MN1 transcript levels, and biologic insights from MN1-associated gene and microRNA expression signatures in cytogenetically normal acute myeloid leukemia: a cancer and leukemia group B study. 1945 32

Minimally differentiated acute myeloid leukemia (AML-M0) is defined by immature morphology and expression of early hematologic markers. By gene expression profiling (GEP) and subsequent unsupervised analysis of 35 AML-M0 samples and 253 previously reported AML cases, we demonstrate that AML-M0 cases express a unique signature that is largely separated from other molecular subtypes. Hematologic transcription regulators such as CEBPA, CEBPD, and ETV6, and the differentiation associated gene MPO appeared strongly down-regulated, in line with the primitive state of this leukemia. AML-M0 frequently carries loss-of-function RUNX1 mutation. Unsupervised analyses revealed a subdivision between AML-M0 cases with and without RUNX1 mutations. RUNX1 mutant AML-M0 samples showed a distinct up-regulation of B cell-related genes such as members of the B-cell receptor complex, transcription regulators RUNX3, ETS2, IRF8, or PRDM1, and major histocompatibility complex class II genes. Importantly, prediction with high accuracy of the AML-M0 subtype and prediction of patients carrying RUNX1 mutation within this subtype were possible based on the expression level of only a few transcripts. We propose that RUNX1 mutations in this AML subgroup cause lineage infidelity, leading to aberrant coexpression of myeloid and B-lymphoid genes. Furthermore, our results imply that AML-M0, although originally determined by morphology, constitutes a leukemia subgroup.
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PMID:Gene expression profiling of minimally differentiated acute myeloid leukemia: M0 is a distinct entity subdivided by RUNX1 mutation status. 1966 67

Alkylating agents, topoisomerase II inhibitors, ionizing radiation, and other hematotoxins induce DNA damage in hematopoietic stem cells that results in lesions such as balanced and unbalanced chromosome rearrangements, -5/del(5q) and/or -7/del(7q), as well as other submicroscopic genetic lesions. Together with epigenetic alterations, these result in dysplasia, clonal expansion, and ultimately myeloid leukemia. Combinations of lesions are required to induce overt leukemia. Altering a small subset of signaling pathways leads to disruption of normal self-renewal, proliferation, differentiation, and apoptotic mechanisms that control the development of hematopoietic stem cells and their differentiation into mature effector cells. Recent studies have shown that cytogenetically normal (CN-) AML is quite heterogeneous at the molecular level. Patients with CN-AML harboring mutations in NPM1, FLT3, CEBPA, WT1 or expressing high levels of BAALC, ERG, or MN1 have distinctly different clinical outcomes. NPM1 mutations are independently associated with higher remission rates and longer disease-free and overall survival in AML. Copy number alterations (CNAs) are deletions or amplifications of single genes. CNAs have been found at the breakpoints of known chromosomal translocations. Fewer CNAs have been detected in AML than in pediatric ALL. Micro-RNAs (miRs) are non-coding small RNA molecules containing about 22 nucleotides that are typically encoded within introns. They hybridize to complementary mRNA targets and modulate protein expression by inhibiting translation and/or inducing degradation of target messenger RNAs. This new class of genes has recently been shown to play a pivotal role in malignant transformation. miRs are down-regulated in many tumors and thus appear to function as tumor suppressor genes. Distinctive genome-wide miR expression profiles have been associated with different subsets of AML. A miR signature that is associated with clinical outcome in patients with high-risk molecular features of AML (those who have FLT3-ITD or wild-type NPM1) has been reported. This subgroup constitutes approximately 65% of patients with CN-AML and one-third of all patients with AML <60 years old. Down-regulation of the miR-181 family contributes to an aggressive leukemia phenotype through mechanisms associated with the activation of pathways of innate immunity mediated by toll-like receptors and interleukin-1beta.
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PMID:Micro-RNAs and copy number changes: new levels of gene regulation in acute myeloid leukemia. 1982 34

Myeloid leukemia in this series corresponds to the myeloid neoplasms of the 4th WHO classification of pathology and genetics of tumor of haematopoietic and lymphoid tissue. The myeloid neoplasms are composed of six categories, which are 1) myeloproliferative neoplasms (MPN), a new category of 2) myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB or FGFR1, 3) myelodysplastic syndrome (MDS)/MPN, 4) MDS, 5) acute myeloid leukemia (AML) and related precursor neoplasms, and 6) acute leukemias of ambiguous lineage. In MPNs without chronic myelogenous leukemia, the genetic marker of JAK2 V617F is added to the diagnostic criteria for polycythemia vera, essential thrombocythemia and primary myelofibrosis. MDS has the new subtype of refractory cytopenia with unilineage dysplasia composed of refractory anemia, refractory neutropenia and refractory thrombocytopenia. AML with t(9; 11) (p22;q23); MLLT3-MLL, AML with t(6;9) (p23; q34); DEK-NUP214, AML with inv(3) (q21q26.2) or t(3; 3) (q21 ; q26.2); RPN1-EVI1 and AML (megakaryoblastic) with t(1; 22) (p13; q13); RBM15-MKL1 are added to the subtype of AML with recurrent genetic abnormalities, and AML with gene mutations of NPM1 and CEBPA are also added as provisional entities of it. The myeloid neoplasms of the 4th WHO classification are comprehensive and seem to be dynamic by incorporating the results of leukemia researches.
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PMID:[Classification of myeloid leukemias]. 1986 Jan 79

We here use knockin mutagenesis in the mouse to model the spectrum of acquired CEBPA mutations in human acute myeloid leukemia. We find that C-terminal C/EBPalpha mutations increase the proliferation of long-term hematopoietic stem cells (LT-HSCs) in a cell-intrinsic manner and override normal HSC homeostasis, leading to expansion of premalignant HSCs. However, such mutations impair myeloid programming of HSCs and block myeloid lineage commitment when homozygous. In contrast, N-terminal C/EBPalpha mutations are silent with regards to HSC expansion, but allow the formation of committed myeloid progenitors, the templates for leukemia-initiating cells. The combination of N- and C-terminal C/EBPalpha mutations incorporates both features, accelerating disease development and explaining the clinical prevalence of this configuration of CEBPA mutations.
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PMID:Hematopoietic stem cell expansion precedes the generation of committed myeloid leukemia-initiating cells in C/EBPalpha mutant AML. 1987 71

We hypothesized that DNA methylation distributes into specific patterns in cancer cells, which reflect critical biological differences. We therefore examined the methylation profiles of 344 patients with acute myeloid leukemia (AML). Clustering of these patients by methylation data segregated patients into 16 groups. Five of these groups defined new AML subtypes that shared no other known feature. In addition, DNA methylation profiles segregated patients with CEBPA aberrations from other subtypes of leukemia, defined four epigenetically distinct forms of AML with NPM1 mutations, and showed that established AML1-ETO, CBFb-MYH11, and PML-RARA leukemia entities are associated with specific methylation profiles. We report a 15 gene methylation classifier predictive of overall survival in an independent patient cohort (p < 0.001, adjusted for known covariates).
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PMID:DNA methylation signatures identify biologically distinct subtypes in acute myeloid leukemia. 2012 41

Cytogenetic aberrations are important prognostic factors in acute myeloid leukemia (AML). However, about 50% of newly diagnosed acute myeloid leukemia (AML) cases have normal karyotype. These patients are very heterogenous with respect to acquired gene mutations and gene expression changes. The identification of these genetic alterations may lead to improved prognostification and generation of novel risk-adapted therapies. The aim of this work was to study the prognostic impact of mutations in the myeloid transcription factor gene CEBPA (for CCAAT/enhancer binding protein-alpha) and expression of the BAALC gene (for brain and acute leukemia, cytoplasmic), a novel gene involved in leukemia, in 38 adults with AML and normal cytogenetics. Screening for mutations of CEBPA gene was assessed using PCR-single-strand conformation polymorphism (PCR-SSCP), and BAALC expression was determined by real-time reverse transcriptase polymerase chain reaction in blood or bone marrow samples. CEBPA mutations were found in 7 (18.4%) of 38 patients, 36.8 % (14 of 38) had low BAALC expression and 63.2 % (24 of 38) had high BAALC expression. Patients with CEBPA mutations had favorable course of their disease. They had higher rate of complete remission (CR) (85.7 % vs 51.6 %; P = 0.108), lower incidence of relapse (0% vs. 41.9%; P = 0.038). Disease free survival (DFS) and overall survival (OS) were significantly longer for patients with CEBPA mutations compared with patients without mutations (mean 13.65 +/- 5.41 vs. 7.32 +/- 4.33 months, P = 0.047; mean 15.32 +/- 6.5 vs 8.5 +/- 3.21 months, P = 0.039; respectively). Compared to low BAALC expressers, high BAALC expressers had lower incidence of CR (50% vs 71.4%; P = 0.171), higher incidence of relapse (50% vs. 14.3%; P = 0.029), and showed significantly shorter DFS (mean 7.5 +/- 2.12 vs. 11.67 +/- 4.6 months, P = 0.038) and inferior overall survival (mean 9.1 +/- 3.52 vs. 13.22 +/- 4.21 months, P = 0.024). On multivariable analysis, wild-type CEBPA as well as high BAALC expression were confirmed as independent risk factors predicting inferior DFS (CEBPA, hazard ratio 0.066, P = 0.001; BAALC, hazard ratio 3.98, P = 0.003) and inferior OS (CEBPA, hazard ratio 0.125, P = 0.002; BAALC, hazard ratio 4.215, P = 0.001). Data obtained in this study suggest that CEBPA mutation status and BAALC expression are important prognostic factors in AML patients with normal cytogenetics and their incorporation into novel risk-adapted therapeutic strategies may improve the currently disappointing cure rate of this group of patients.
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PMID:Prognostic significance of CEBPA mutations and BAALC expression in acute myeloid leukemia Egyptian patients with normal karyotype. 2030 78


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