Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatic mutations in nucleophosmin (NPM1) occur in approximately 35% of adult acute myeloid leukemia (AML). To assess the frequency of NPM1 mutations in pediatric AML, we sequenced NPM1 in the diagnostic blasts from 93 pediatric AML patients. Six cases harbored NPM1 mutations, with each case lacking common cytogenetic abnormalities. To explore the phenotype of the AMLs with NPM1 mutations, gene expression profiles were obtained using Affymetrix U133A microarrays. NPM1 mutations were associated with increased expression of multiple homeobox genes including HOXA9, A10, B2, B6 and MEIS1. As dysregulated homeobox gene expression is also a feature of MLL-rearranged leukemia, the gene expression signatures of NPM1-mutated and MLL-rearranged leukemias were compared. Significant differences were identified between these leukemia subtypes including the expression of different HOX genes, with NPM1-mutated AML showing higher levels of expression of HOXB2, B3, B6 and D4. These results confirm recent reports of perturbed HOX expression in NPM1-mutated adult AML, and provide the first evidence that the NPM1-mutated signature is distinct from MLL-rearranged AML. These findings suggest that mutated NPM1 leads to dysregulated HOX expression via a different mechanism than MLL rearrangement.
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PMID:Pediatric acute myeloid leukemia with NPM1 mutations is characterized by a gene expression profile with dysregulated HOX gene expression distinct from MLL-rearranged leukemias. 1771 59

Creation of a nuclear export signal (NES) motif and loss of tryptophans (W) 288 and 290 (or 290 only) at the COOH terminus of nucleophosmin (NPM) are both crucial for NPM aberrant cytoplasmic accumulation in acute myelogenous leukemia (AML) carrying NPM1 mutations. Hereby, we clarify how these COOH-terminal alterations functionally cooperate to delocalize NPM to the cytoplasm. Using a Rev(1.4)-based shuttling assay, we measured the nuclear export efficiency of six different COOH-terminal NES motifs identified in NPM mutants and found significant strength variability, the strongest NES motifs being associated with NPM mutants retaining W288. When artificially coupled with a weak NES, W288-retaining NPM mutants are not exported efficiently into cytoplasm because the force (W288) driving the mutants toward the nucleolus overwhelms the force (NES) exporting the mutants into cytoplasm. We then used this functional assay to study the physiologic NH(2)-terminal NES motifs of wild-type NPM and found that they are weak, which explains the prominent nucleolar localization of wild-type NPM. Thus, the opposing balance of forces (tryptophans and NES) seems to determine the subcellular localization of NPM. The fact that W288-retaining mutants always combine with the strongest NES reveals mutational selective pressure toward efficient export into cytoplasm, pointing to this event as critical for leukemogenesis.
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PMID:Born to be exported: COOH-terminal nuclear export signals of different strength ensure cytoplasmic accumulation of nucleophosmin leukemic mutants. 1761 80

NPM1 mutations have been reported to be the most frequent mutations in acute myeloid leukemia (AML). They are associated with a wide spectrum of morphologic subtypes of AML, normal karyotype and FLT3 mutations. The high frequency of NPM1 mutations might provide a suitable marker for monitoring residual disease of AML.
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PMID:NPM1 mutations are more stable than FLT3 mutations during the course of disease in patients with acute myeloid leukemia. 1776 24

Many European groups have recently described that mutations at exon-12 of the nucleophosmin (NPM1) gene are the most frequent genetic lesion in patients with acute myeloid leukemia (AML), especially in the presence of a normal karyotype. This study explored the prevalence and clinical profile of NPM1 mutations in a cohort of 156 Chinese adults with AML. NPM1 exon-12 mutations were detected using direct sequencing or fragment analysis of genomic DNA polymerase chain reaction products. NPM1 mutations were present in 28.2% of the overall population, including 1/1 (100%) of M0, 11/27 (40.7%) of M1, 11/46 (23.9%) of M2, 0/29 (0%) of M3, 2/9 (22.2%) of M4, 18/39 (46.2%) of M5, and 1/5 (20.0%) of M6. NPM1 gene mutations were more prevalent in patients with a normal karyotype (37 of 90; 41.1%) when compared with patients with karyotypic abnormalities (7 of 66; 10.6%;P < .001). Sequence analysis of 25 NPM1-mutated cases revealed known mutations (type A, D, N(M), and P(M)) as well as one novel sequence variation (here named as type S). All mutational types were heterozygous and showed a 4 bp insertion. NPM1 mutations were significantly associated with old age (P < .05), high peripheral white blood cell count (P < .05), and the subtypes of French-American-British categories M1/M5, but negatively associated with expression of CD34 (P < .05) and CD117 (P < .05). Thus, this study provides the methods of NPM1 exon-12 mutations detection and related clinical data of NPM1 mutated cases in a Chinese population.
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PMID:Analysis of NPM1 gene mutations in Chinese adults with acute myeloid leukemia. 1787 28

The prognostic relevance of FLT3 D835/I836 mutations (FLT3-TKD) in cytogenetically normal acute myeloid leukemia (CN-AML) remains to be established. After excluding patients with FLT3 internal tandem duplications, we compared treatment outcome of 16 de novo CN-AML patients with FLT3-TKD with that of 123 patients with wild-type FLT3 (FLT3-WT), less than 60 years of age and similarly treated on Cancer and Leukemia Group B protocols. All FLT3-TKD(+) patients and 85% of FLT3-WT patients achieved a complete remission (P = .13). Disease-free survival (DFS) of FLT3-TKD(+) patients was worse than DFS of FLT3-WT patients (P = .01; estimated 3-year DFS rates, 31% vs 60%, respectively). In a multivariable analysis, FLT3-TKD was associated with worse DFS (P = .02) independent of NPM1 status and percentage of bone marrow blasts. To gain further biologic insights, a gene-expression signature differentiating FLT3-TKD(+) from FLT3-WT patients was identified. The signature (333 probe sets) included overexpression of VNN1, C3AR1, PTPN6, and multiple other genes involved in monocarboxylate transport activity, and underexpression of genes involved in signal transduction regulation. These associations with outcome, other prognostic markers, and the elucidated expression signature enhance our understanding of FLT3-TKD-associated biology and may lead to development of novel therapies that improve clinical outcome of CN-AML patients with FLT3-TKD.
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PMID:FLT3 D835/I836 mutations are associated with poor disease-free survival and a distinct gene-expression signature among younger adults with de novo cytogenetically normal acute myeloid leukemia lacking FLT3 internal tandem duplications. 1860 88

The balance between proangiogenic Angiopoietin-1 (Ang-1) and the antagonistic Ang-2 is important both for leukemogenesis and chemosensitivity in human acute myelogenous leukemia (AML). We examined the release of Ang-1 and Ang-2 by AML cells cultured alone and in cocultures with stromal cells. Detectable Ang-1 release from AML cells was observed for most patients (62/91), whereas Ang-2 release was detected only for a minority (23/91). Coculture of AML and stromal cells led to increased Ang-1 levels. Furthermore, the role of the angiopoietin system was investigated by characterizing whether the differences in angiopoietin expression in AML patients can be related to nucleophosmin (NPM1) mutations. We compared the gene expression profiles of AML cells derived from 19 patients with FLT3 mutations and normal cytogenetics with and without NPM1 mutations and observed increased expression of Ang-1 in patients with NPM1 mutations. Finally, we found significantly higher Ang-2 levels in serum of AML patients compared with healthy controls. Our results suggest that AML cells are a major source of Ang-1 in leukemic bone marrow, especially in patients with NPM1 mutations, but the local levels are also influenced by stromal cells. Local Ang-2 release from AML cells is less common, but high systemic levels of Ang-2 may affect bone marrow angioregulation.
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PMID:Release of angiopoietin-1 by primary human acute myelogenous leukemia cells is associated with mutations of nucleophosmin, increased by bone marrow stromal cells and possibly antagonized by high systemic angiopoietin-2 levels. 1794 67

We characterized the mutational status of the FLT3 tyrosine kinase domain (FLT3-TLD) in 3082 patients with newly diagnosed AML. FLT3-TKD mutations were detected in 147 of 3082 (4.8%) patients. Similar to the FLT3 juxtamembrane domain mutations (FLT3-LM), there was a high correlation of FLT3-TKD mutations with normal karyotype (88 of 1472; 6.0%). FLT3-TKD mutations were most frequent in the AML FAB subtypes M5b (15 of 114; 13.2%), M3v (6 of 51; 11.8%), and M4 (39 of 484; 8.1%). Similar to FLT3-LM, the FLT3-TKD mutations show elevated peripheral leukocytes compared with FLT3wt AML. FLT3-TKD had a high incidence in cases with NPM1 mutations (23 of 262; 8.8%), CEBPA mutations (6 of 76; 7.9%), and NRAS mutations (6 of 78; 7.7%). FLT3-TKD in combination with FLT3-LM (17 of 594 patients; 2.9%) and KITD816 (1 of 44; 2.3%) was rare. Unlike the FLT3-LM, which are associated with inferior survival, prognosis was not influenced by FLT3-TKD in the total cohort of 1720 cases, where follow-up data were available (97 FLT3-TKD; 1623 FLT3-WT). In t(15;17)/PML-RARA with FLT3-TKD mutations, in FLT3-LM/TKD double-mutated, and in MLL-PTD/TKD double-mutated cases prognosis was unfavorably influenced by FLT3-TKD mutations. In contrast, we found an additional favorable impact of FLT3-TKD on EFS in prognostically favorable AML with NPM1- or CEBPA mutations.
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PMID:Prognostic relevance of FLT3-TKD mutations in AML: the combination matters--an analysis of 3082 patients. 1796 22

Nucleophosmin (NPM1) gene exon 12 mutations are frequently present in patients with acute myeloid leukemia (AML) with normal karyotype. The NPM1 gene is located on chromosome 5q35, which is often affected in myeloid malignancies including myelodysplastic syndrome (MDS). This suggests that the NPM1 gene is a one of the target genes affected by chromosome 5 abnormalities and play a role in the development of MDS. It has not been clarified whether MPM1 mutations are present in patients with MDS and AML with chromosome 5 abnormalities. Therefore, we carried out a mutational analysis on the NPM1 gene exon 12. NPM1 mutations were not detected in the 28 patients with MDS and AML with chromosome 5 abnormalities.
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PMID:Lack of nucleophosmin mutation in patients with myelodysplastic syndrome and acute myeloid leukemia with chromosome 5 abnormalities. 1799 Jan 74

Two highly sensitive methods, multiparameter flow cytometry (MFC) and real-time quantitative PCR (RQ-PCR), are increasingly used to monitor minimal residual disease (MRD) and to guide risk-adapted management in acute myeloid leukemia (AML). An independent prognostic impact has been demonstrated for MRD levels obtained by both methods. MFC has been found particularly useful for assessment of early clearance of malignant cells and after consolidation therapy. At the latter checkpoint, MRD levels quantified by RQ-PCR in AML with fusion genes also have the strongest prognostic power. In addition, highly predictive initial expression levels have been identified by RQ-PCR. Both methods are capable of early detection of relapse. Through the use of all available markers including NPM1 mutations and FLT3 mutations in addition to fusion genes, RQ-PCR-based MRD assessment is possible in more than half of patients, whereas MFC is applicable to most AML cases. With a sensitivity of 10(-4) (PML-RARA) to 10(-7) (patient-specific primers, FLT3 and NPM1 mutations), RQ-PCR is more sensitive in most cases. Large clinical trials will determine the exact role and place of immunologic and RQ-PCR-based monitoring of MRD in the therapy of patients with AML.
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PMID:Monitoring of minimal residual disease in acute myeloid leukemia. 1800 Aug 11

Between February 1996 and December 2004, the German Leukemia Study Initiative registered 1766 consecutive patients for the acute myeloid leukemia (AML) 96 study, all of whom were diagnosed by central cytomorphology according to the French-American-British (FAB) and the new World Health Organization (WHO) classification. We focused our analysis on the prognostic impact of multilineage dysplasia (MLD) as a new parameter of the WHO classification for AML. We could not confirm the WHO statement that MLD occurs most frequently in older individuals, but we confirmed that MLD is often associated with an unfavorable cytogenetic profile (P < .001). In 1332 individuals receiving intensive AML therapy presence of MLD was negatively correlated with complete remission (P = .001) in univariate, but not in multivariate, analysis. Multivariate analysis of either event-free or overall survival again failed to show an independent prognostic significance of MLD besides age, cytogenetics, and, in part, NPM1/FLT3-ITD mutations. Our data support a reassessment of the WHO classification in the light of a more biologic understanding of AML. This study is registered at www.ClinicalTrials.gov as #NCT00180115.
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PMID:MLD according to the WHO classification in AML has no correlation with age and no independent prognostic relevance as analyzed in 1766 patients. 1805 40


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