Distinct clinical and biological implications of various DNMT3A mutations in myeloid neoplasms.
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ABSTRACT:
SUBMITTER: Balasubramanian SK
PROVIDER: S-EPMC8404553 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Somatic mutations of the CUT-like homeobox 1 (CUX1) gene (CUX1 MT) can be found in myeloid neoplasms (MNs), in particular, in myelodysplastic syndromes (MDSs). The CUX1 locus is also deleted in 3 of 4 MN cases with -7/del(7q). A cohort of 1480 MN patients was used to characterize clinical features and clonal hierarchy associated with CUX1 MT and CUX1 deletions (CUX1 DEL) and to analyze their functional consequences in vitro. CUX1 MT were present in 4% of chronic MNs. CUX1 DEL were preferentially found in advanced cases (6%). Most MDS and acute myeloid leukemia (AML) patients with -7/del(7q) and up to 15% of MDS patients and 5% of AML patients diploid for the CUX1 locus exhibited downmodulated CUX1 expression. In 75% of mutant cases, CUX1 MT were heterozygous, whereas microdeletions and homozygous and compound-heterozygous mutations were less common. CUX MT/DEL were associated with worse survival compared with CUX1 WT Within the clonal hierarchy, 1 of 3 CUX1 MT served as founder events often followed by secondary BCOR and ASXL1 subclonal hits, whereas TET2 was the most common ancestral lesion, followed by subclonal CUX1 MT Comet assay of patients' bone marrow progenitor cells and leukemic cell lines performed in various experimental conditions revealed that frameshift mutations, hemizygous deletions, or experimental CUX1 knockdown decrease the repair of oxidized bases. These functional findings may explain why samples with either CUX1 MT or low CUX1 expression coincided with significantly higher numbers of somatic hits by whole-exome sequencing. Our findings implicate the DNA repair dysfunction resulting from CUX1 lesions in the pathogenesis of MNs, in which they lead to a mutator phenotype.
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Project description:Mutations in isocitrate dehydrogenase 1/2 (IDH1/2(MT)) are drivers of a variety of myeloid neoplasms. As they yield the same oncometabolite, D-2-hydroxyglutarate, they are often treated as equivalent, and pooled. We studied the validity of this approach and found IDH1/2 mutations in 179 of 2119 myeloid neoplasms (8%). Cross-sectionally, the frequencies of these mutations increased from lower- to higher risk disease, thus suggesting a role in clinical progression. Variant allelic frequencies indicated that IDH1(MT) and IDH2(MT) are ancestral in up to 14/74 (19%) vs 34/99 (34%; P=0.027) of cases, respectively, illustrating the pathogenic role of these lesions in myeloid neoplasms. IDH1/2(MT) was associated with poor overall survival, particularly in lower risk myelodysplastic syndromes. Ancestral IDH1(MT) cases were associated with a worse prognosis than subclonal IDH1(MT) cases, whereas the position of IDH2(MT) within clonal hierarchy did not impact survival. This may relate to distinct mutational spectra with more DNMT3A and NPM1 mutations associated with IDH1(MT) cases, and more ASXL1, SRSF2, RUNX1, STAG2 mutations associated with IDH2(MT) cases. Our data demonstrate important clinical and biological differences between IDH1(MT) and IDH2(MT) myeloid neoplasms. These mutations should be considered separately as their differences could have implications for diagnosis, prognosis and treatment with IDH1/2(MT) inhibitors of IDH1/2(MT) patients.
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Project description:The genetic alterations responsible for an adverse outcome in most patients with acute myeloid leukemia (AML) are unknown.Using massively parallel DNA sequencing, we identified a somatic mutation in DNMT3A, encoding a DNA methyltransferase, in the genome of cells from a patient with AML with a normal karyotype. We sequenced the exons of DNMT3A in 280 additional patients with de novo AML to define recurring mutations.A total of 62 of 281 patients (22.1%) had mutations in DNMT3A that were predicted to affect translation. We identified 18 different missense mutations, the most common of which was predicted to affect amino acid R882 (in 37 patients). We also identified six frameshift, six nonsense, and three splice-site mutations and a 1.5-Mbp deletion encompassing DNMT3A. These mutations were highly enriched in the group of patients with an intermediate-risk cytogenetic profile (56 of 166 patients, or 33.7%) but were absent in all 79 patients with a favorable-risk cytogenetic profile (P<0.001 for both comparisons). The median overall survival among patients with DNMT3A mutations was significantly shorter than that among patients without such mutations (12.3 months vs. 41.1 months, P<0.001). DNMT3A mutations were associated with adverse outcomes among patients with an intermediate-risk cytogenetic profile or FLT3 mutations, regardless of age, and were independently associated with a poor outcome in Cox proportional-hazards analysis.DNMT3A mutations are highly recurrent in patients with de novo AML with an intermediate-risk cytogenetic profile and are independently associated with a poor outcome. (Funded by the National Institutes of Health and others.).
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Project description:Mutations in DNA methyltransferase 3A (DNMT3A) gene were recently demonstrated in acute myeloid leukemia(AML). Approximately 20% patients with AML carry DNMT3A gene mutations and was associated with a poor clinical outcome. but its clinical implications in Chinese AML patients are largely unknown. We analyzed 101 adult AML patients in china and found 14 patients (13.9%) harboring this mutation. 9 patient with M5, 2 patients with M1, 2patient with M2 and 1 patient with M3. We identified 11 missense mutation,2 nonsense and 30 bp deletion encompassing DNMT3A. The most common of them was predicted to affect 882Arg(in 4 patients). Double mutations were detected in two cases.10 of 33(43.5%). DNMT3A mutations occurred more frequently in older (age > 50y,p < 0.05) and the outcome is too badly for these patients. We concluded that DNMT3A mutations are highly recurrent in AML and is associated with distinct clinical and biologic characteristics and seems to be a useful as a prognostic marker.
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Project description:BACKGROUND: Mutations in epigenetic modifiers were reported in patients with acute myeloid leukaemia (AML) including mutations in DNA methyltransferase 3A gene (DNMT3A) in 20%-30% patients and mutations in isocitrate dehydrogenase 1/2 gene (IDH1/2) in 5%-15% patients. Novel studies have shown that mutations in DNMT3A and IDH1/2 influence prognosis, indicating an increasing need to detect these mutations during routine laboratory analysis. DNA sequencing for the identification of these mutations is time-consuming and cost-intensive. This study aimed to establish rapid screening tests to identify mutations in DNMT3A and IDH1/2 that could be applied in routine laboratory procedures and that could influence initial patient management. METHODS: In this study we developed an endonuclease restriction method to identify the most common DNMT3A mutation (R882H) and an amplification-refractory mutation system (ARMS) to analyse IDH2 R140Q mutations. Furthermore, we compared these methods with HRM analysis and evaluated the latter for the detection of IDH1 mutations. RESULTS: Of 230 samples from patients with AML 30 (13%) samples had DNMT3A mutations, 16 (7%) samples had IDH2 R140Q mutations and 36 (16%) samples had IDH1 mutations. Sensitivity assays performed using serial dilutions of mutated DNA showed that ARMS analysis had a sensitivity of 4.5%, endonuclease restriction had a sensitivity of 0.05% and HRM analysis had a sensitivity of 5.9%-7.8% for detecting different mutations. HRM analysis was the best screening method to determine the heterogeneity of IDH1 mutations. Furthermore, for the identification of mutations in IDH2 and DNMT3A, endonuclease restriction and ARMS methods showed a perfect concordance (100%) with Sanger sequencing while HRM analysis showed a near-perfect concordance (approximately 98%). CONCLUSION: Our study suggested that all the developed methods were rapid, specific and easy to use and interpret. HRM analysis is the most timesaving and cost-efficient method to rapidly screen all the 3 genes at diagnosis in samples obtained from patients with AML. Endonuclease restriction and ARMS assays can be used separately or in combination with HRM analysis to obtain more reliable results. We propose that early screening of mutations in patients with AML having normal karyotype could facilitate risk stratification and improve treatment options.
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