Among patients with AML, the detection of molecular minimal residual disease during complete remission had significant independent prognostic value with respect to relapse and survival rates, but the detection of persistent mutations that are associated with clonal hematopoiesis did not have such prognostic value within a 4-year time frame. (Funded by the Queen Wilhelmina Fund Foundation of the Dutch Cancer Society and others.).

Somatic mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) were recently demonstrated in acute myeloid leukemia (AML), but their prevalence and prognostic impact remain to be explored in large extensively characterized AML series, and also in various other hematologic malignancies. Here, we demonstrate in 893 newly diagnosed cases of AML mutations in the IDH1 (6%) and IDH2 (11%) genes. Moreover, we identified IDH mutations in 2 JAK2 V617F myeloproliferative neoplasias (n ‫؍‬ 96), a single case of acute lymphoblastic leukemia (n ‫؍‬ 96), and none in chronic myeloid leukemias (n ‫؍‬ 81). In AML, IDH1 and IDH2 mutations are more common among AML with normal karyotype and NPM1 mutant genotypes. IDH1 mutation status is an unfavorable prognostic factor as regards survival in a composite genotypic subset lacking IntroductionSomatic mutations in the genes encoding the isocitrate dehydrogenases IDH1 and IDH2 were revealed in more than 70% of World Health Organization grade 2 and 3 astrocytomas, oligodendrogliomas, and glioblastomas. [1][2][3] Mutations in IDH1 and IDH2 were mutually exclusive and affected the arginines on position 132 of IDH1 and position 172 of IDH2. 3 Patients with malignant gliomas with IDH1 or IDH2 mutations showed a better response to therapy than those with wild-type IDH genes. 3 Mutations in these residues of IDH significantly disturb the function of both isocitrate dehydrogenases, as demonstrated by impaired production of nicotinamide adenine dinucleotide phosphate. 3,4 In acute myeloid leukemia (AML), mutant IDH enzyme activity results in accumulation of the cancer-associated metabolite 2-hydroxyglutarate. 5,6 Recently, acquired mutations in the gene encoding IDH1 were identified in 8% 7 and 5.5% 8 of newly diagnosed AML cases. IDH1 mutations were significantly associated with normal karyotype and NPM1 mutations. 7,8 Overall, the IDH1 mutation status did not suggest a relationship with overall survival (OS), but the sample sizes were limited in these studies. 7,8 However, a trend for an adverse effect on OS was suggested in normal karyotype AML with NPM1 wild-type . 7 The prevalence and prognostic value of IDH mutations in AML, as well as other hematologic malignancies, remain to be further established. In this study, we determined the frequencies of both IDH1 and IDH2 mutations in cohorts of AML, acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML), and JAK2 V617F myeloproliferative neoplasia (MPN). In a cohort of 893 cases of AML, we investigated their distribution in relationship with cytogenetic and molecular risk categories as well as recurrent gene mutations commonly apparent in AML, and we evaluated the impact of IDH mutations on treatment outcome. MethodsBone marrow aspirates or peripheral blood samples of cohorts of patients with various hematologic malignancies were collected after written informed consent in accordance with the Declaration of Helsinki. All experiments described were approved by the Erasmus University Medical Center Institutional Review Board....

The prevalence, the prognostic effect, and interaction with other molecular markers of DNMT3A mutations was studied in 415 patients with acute myeloid leukemia (AML) younger than 60 years. We show mutations in DNMT3A

Key Points• inv(3)/t(3;3) disease exhibits high rates of activated RAS/ RTK signaling, epigenetic modifier, splice, and transcription factor mutations.• AML and MDS with inv(3)/t(3;3) display similar mutational and gene expression profiles and should be considered a single molecular entity.Myeloid malignancies bearing chromosomal inv(3)/t(3;3) abnormalities are among the most therapy-resistant leukemias. Deregulated expression of EVI1 is the molecular hallmark of this disease; however, the genome-wide spectrum of cooperating mutations in this disease subset has not been systematically elucidated. Here, we show that 98% of inv(3)/t(3;3) myeloid malignancies harbor mutations in genes activating RAS/receptor tyrosine kinase (RTK) signaling pathways. In addition, hemizygous mutations in GATA2, as well as heterozygous alterations in RUNX1, SF3B1, and genes encoding epigenetic modifiers, frequently co-occur with the inv(3)/t(3;3) aberration. Notably, neither mutational patterns nor gene expression profiles differ across inv(3)/t(3;3) acute myeloid leukemia, chronic myeloid leukemia, and myelodysplastic syndrome cases, suggesting recognition of inv(3)/t(3;3) myeloid malignancies as a single disease entity irrespective of blast count. The high incidence of activating RAS/RTK signaling mutations may provide a target for a rational treatment strategy in this high-risk patient group. (Blood. 2015;125(1):133-139) IntroductionAcute myeloid leukemia (AML) with inv(3)(q21q26.2) or t(3;3)(q21;q26.2) [inv(3)/t(3;3)] is a distinct disease entity in the current World Health Organization classification. 1 High therapy resistance is the common feature of myeloid malignancies, particularly AML with 3q21/3q26 aberrations, manifesting as low rates of complete remission and subsequent failure of current treatment strategies. [2][3][4] Appearance of the characteristic 3q aberrations also indicates disease progression and portends adverse outcome in myelodysplastic syndrome (MDS) and chronic myeloid leukemia (CML). [5][6][7] Therapy resistance in this subtype of malignancies is linked to the inappropriate activation of the proto-oncogene ecotropic viral integration-1 (EVI1) as a consequence of the chromosome 3 rearrangements. EVI1 is a hematopoietic stemness factor and transcription factor with chromatin-remodeling activity.8-10 EVI1 is also overexpressed in approximately 11% of all AML cases in the absence of 3q aberrations and represents an independent adverse prognostic factor in these patients. 11 We and others have shown that, as a consequence of inv(3)/t(3;3) rearrangements, EVI1 becomes activated via structural repositioning of a distal GATA2 enhancer from 3q21 to the EVI1 locus at 3q26. 12,13 Relocation of the enhancer additionally confers reduced and monoallelic GATA2 expression in this AML subtype.Notably, GATA2 deficiency has been shown to impair hematopoietic stem cell frequency and fitness, [14][15][16] and Evi1 activation in murine inv(3)/t(3;3) models is followed by leukemia onset after a long latency of 6 months.13 Hen...

In this study, molecular simulations have been combined with site-directed mutagenesis experiments to explore M398(2.43), a LH (lutropin) receptor (LHR) site in helix 2 susceptible to spontaneous activating mutations, and to develop a computational tool for predicting the functionality (i.e. active or nonactive) of LHR mutants.Site-directed mutagenesis experiments engineered 15 different substitutions for M389(2.43), which resulted in variable levels of constitutive activity, inversely correlated with the size of the replacing amino acid. This inverse correlation is suggested to be mediated by I460(3.46), M571(6.37), and Y623(7.53), the tyrosine of the NPxxY motif. In fact, size reduction at position 398(2.43), which is concurrent with constitutive receptor activity, releases the van der Waals interactions found in the wild-type LHR between M398(2.43) and these three amino acids, resulting in structural modifications in the proximity to the E/DRY/W motif. An increment, above a threshold value, in the solvent accessibility of the cytosolic ends of helices 3 and 6 is the main structural feature shared by the active mutants of the LHR. This feature has been successfully used for predicting the functionality of the engineered mutants at M398(2.43), proving that molecular simulations can be useful for in silico screening of LHR mutants.