De novo acute myeloid leukemia (AML) with concurrent DNMT3A, FLT3 and NPM1 mutations (AML DNMT3A/FLT3/NPM1 ) has been suggested to represent a unique AML subset on the basis of integrative genomic analysis, but the clinical features of such patients have not been characterized systematically. We assessed the features of patients (n = 178) harboring mutations in DNMT3A, FLT3 and/or NPM1, including an index group of AML DNMT3A/FLT3/NPM1 patients. Patients with AML DNMT3A/FLT3/NPM1 (n = 35) were significantly younger (median, 56.0 vs. 62.0 years; p = 0.025), mostly women (65.7% vs. 46.9%; p = 0.045), and presented with a higher percentage of bone marrow blasts (p < 0.001) and normal cytogenetics (p = 0.024) in comparison to patients within other mutation groups in this study. Among patients <60 years old, those with AML DNMT3A/FLT3/NPM1 had a shorter event-free survival (EFS) (p = 0.047). DNMT3A mutations and not FLT3 or NPM1 mutations were independently associated with overall survival (OS) (p = 0.026). Within mutation subgroups, patients with AML DNMT3A/NPM1 had a significantly shorter OS compared to those with AML FLT3-ITD/NPM1 (p = 0.047) suggesting that the adverse impact of DNMT3A mutations is more pronounced than that of FLT3- ITD among patients with NPM1 mutation. DNMT3A has a significant dominant effect on the clinical features and outcomes of de novo AML patients with concurrent DNMT3A, FLT3 and NPM1 mutations.

Circulating microRNAs (miRNAs) are potential biomarkers for cancer. We examined plasma levels of 2 miRNAs, let-7a and miR-16, in 50 patients with myelodysplastic syndrome (MDS) and 76 healthy persons using quantitative real-time PCR. Circulating levels of both miRNAs were similar among healthy controls but were significantly lower in MDS patients (P = .001 and P < .001, respectively). The distributions of these 2 miRNA levels were bimodal in MDS patients, and these levels were significantly associated with their progression-free survival and overall survival (both P < .001 for let-7a; P < .001 and P = .001 for miR-16). This association persisted even after patients were stratified according to the International Prognostic Scoring System. Multivariate analysis revealed that let-7a level was a strong independent predictor for overall survival in this patient cohort. These findings suggest that let-7a and miR-16 plasma levels can serve as noninvasive prognostic markers in MDS patients.

FMS-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes in acute myeloid leukemia and is associated with worse clinical outcome. Changes in FLT3 mutation status can occur during the course of disease, but the clinical impact of a change is unclear. We retrospectively reviewed 3555 acute myeloid leukemia patients, who have been assessed for FLT3 mutation at our institution between May 2002 and January 2011. We found that 42 (6.2%) out of 680 patients with FLT3 mutation experienced a change of FLT3 mutation status. In all, 36 patients with wild-type FLT3 at the time of initial diagnosis gained mutation (Negative/Positive) and six initially FLT3-mutated patients became wild type during their following relapses (Positive/Negative). The 5-year survival of these patients was similar to that of patients with persistently wild-type FLT3 (Negative/Negative; P=0.464), and significantly better than patients who had stable FLT3 mutation during their disease course (Positive/Positive; P<0.001). However, after mutations became detectable in the Negative/Positive group, the forward survival of these patients tracked that of the Positive/Positive group after relapse (P=0.761). In addition, we did not find a significant difference in survival between patients with internal tandem duplications and those with point mutations in the tyrosine kinase domain of the FLT3 gene. These results suggest that FLT3 mutations are unstable and that there is potential clinical value in continuously monitoring FLT3 mutation status.

Context.—Acute erythroid leukemia (AEL) is an uncommon type of acute myeloid leukemia (AML), representing less than 5% of all cases. Acute erythroid leukemia is characterized by a predominant erythroid proliferation, and in the current World Health Organization (WHO) classification scheme there are 2 subtypes: erythroleukemia (erythroid/myeloid leukemia) and pure erythroid leukemia. Morphologic findings are most important for establishing the diagnosis. The erythroleukemia subtype, which is most common, is defined as the presence of 50% or more erythroid precursors and 20% or more blasts in the nonerythroid component. The pure erythroid leukemia subtype is composed of 80% or more immature erythroblasts. Although these morphologic criteria appear straightforward, AEL overlaps with other types of AML and myelodysplastic syndrome that are erythroid rich. Objective.—To provide an update of AEL, including clinical presentation, morphologic features, immunophenotype, and cytogenetic and molecular data. As the erythroleukemia subtype is most common, the literature and this review are biased towards this subtype of AEL. Data Sources.—Clinicopathologic, cytogenetic, and molecular information were extracted from our review of pertinent literature and a subset of AEL cases in the files of The University of Texas M. D. Anderson Cancer Center (Houston) and University of South Alabama (Mobile). Conclusions.—The current WHO criteria for establishing the diagnosis of AEL reduce the frequency of this entity, as cases once classified as the erythroleukemia subtype are now reclassified as other types of AML, particularly AML with myelodysplasia-related changes and therapy-related AML. This reclassification also may have prognostic significance for patients with the erythroleukemia subtype of AEL. In contrast, the current WHO criteria appear to have little impact on the frequency and poor prognosis of patients with the pure erythroid leukemia subtype of AEL. Molecular studies, preferably using high-throughput methods, are needed for a better understanding of the pathogenesis of AEL, and for developing diagnostic and prognostic markers.

Myelodysplastic syndromes are a heterogeneous group of clonal bone marrow hematopoietic stem cell disorders characterized by ineffective hematopoiesis and peripheral cytopenias. Chromosomal abnormalities and gene mutations have been shown to have essential roles in pathogenesis and correlate with prognosis. Molecular markers, however, are not integrated into currently used prognostic systems. The goal of this study is to identify plasma microRNAs useful for classification and risk stratification of myelodysplastic syndromes. We applied a novel, high-throughput digital quantification technology (NanoString) to profile microRNA expression in plasma samples of 72 patients with myelodysplastic syndromes and 12 healthy individuals. We correlated these results with overall survival. In patients with myelodysplastic syndromes associated with a diploid karyotype, we identified and validated a 7-microRNA signature as an independent predictor of survival with a predictive power of 75% accuracy (P=0.008), better than those of the International Prognostic Scoring Systems and the MD Anderson Prognostic Lower Risk Prognostic Model. We also identified differentially expressed plasma microRNAs in patients with myelodysplastic syndromes versus healthy individuals and between patients with myelodysplastic syndromes associated with different cytogenetic features. These results validate the utility of circulating-microRNA levels as noninvasive biomarkers that can inform the management of patients with myelodysplastic syndromes. Our findings also shed light on interactions of gene regulation pathways that are likely involved in the pathogenesis of myelodysplastic syndromes.

The clinical importance of erythroid predominance in bone marrow of patients with acute myeloid leukemia (AML) is controversial. These cases represent a heterogeneous group of diseases that historically have been classified into different categories. We studied 313 AML patients and specifically compared the clinical, cytogenetic, and molecular features of cases of AML with erythroid predominance, arbitrarily defined as ≥50% erythroid precursors, to AML cases without erythroid predominance. We also assessed 51 patients with a high-grade myelodysplastic syndrome (MDS), refractory anemia with excess blasts (RAEB). All neoplasms were classified according to the World Health Organization classification. With the exception of therapy-related AML/MDS, the presence of erythroid predominance in variously classified categories of AML was associated with a survival advantage. In addition, AML with erythroid predominance had a lower frequency of cytogenetic abnormalities as well as a lower frequency of mutations involving NPM1, NRAS and FLT3 as compared with AML without erythroid predominance. We conclude that the clinical, cytogenetic, and molecular features of AML with erythroid predominance in the non-therapy-related setting are much closer to those of a high-grade myelodysplastic syndrome than they are to other types of AML.