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Treatment of acute myeloid leukemia (AML) remains challenging and novel targets and synergistic therapies still need to be discovered. We performed a high-throughput RNAi screen in three different AML cell lines and primary human leukemic blasts to identify genes that synergize with common antileukemic therapies. We used a pooled shRNA library that covered 5043 different genes and combined transfection with exposure to either azacytidine or cytarabine analog to the concept of synthetic lethality. Suppression of the chemokine CXCL12 ranked highly among the candidates of the cytarabine group. Azacytidine in combination with suppression of genes within the neddylation pathway led to synergistic results. NEDD8 and RBX1 inhibition by the small molecule inhibitor pevonedistat inhibited leukemia cell growth. These findings establish an in vitro synergism between NEDD8 inhibition and azacytidine in AML. Taken together, neddylation constitutes a suitable target pathway for azacytidine combination strategies. [ABSTRACT FROM AUTHOR]

Although completely reversible, transient neurological disturbances (grade 1 dizziness, restlessness, anxiety, taste disturbance; grade 2 encephalopathy) caused the patient not to continue therapy after cycle 2 (administered as compassionate use, since continued therapy after CR was not foreseen by the protocol). Treatment strategies in patients with AML or high-risk myelodysplastic syndrome relapsed after allo-SCT. Besides multiple functions in cellular immunity, interleukin 2 (IL2) causes tumour regression.1-5 Proleukine® [aldesleukin, human recombinant IL2 (rhIL2)] was approved for renal cancer and melanoma. Phase I study of F16IL2 antibody-cytokine fusion with very low-dose araC in acute myeloid leukaemia relapse after allogeneic stem cell transplantation. [Extracted from the article]

Summary: The low‐density lipoprotein receptor (LDLR) is a membrane receptor that mediates the endocytosis of low‐density lipoprotein (LDL). Uptake of LDL has been proposed to contribute to chemotherapy resistance of acute myeloid leukaemia (AML) cell lines invitro. In the present study, we analysed LDLR expression and survival using bone marrow biopsies from 187 intensively treated patients with AML. Here, increasing LDLR expression was associated with decreasing overall (58·4%, 44·2%, and 24·4%; P = 0·0018), as well as event‐free survival (41·7%, 18·1%, and 14·3%; P = 0·0077), and an increasing cumulative incidence of relapse (33·9%, 55·1%, and 71·4%; P = 0·0011). Associations of LDLR expression with survival were confirmed in 557 intensively treated patients from two international validation cohorts. In the analytic and validation cohorts, LDLR expression remained associated with outcome in multivariable regression analyses including the European LeukemiaNet genetic risk classification. Thus, LDLR predicts outcome of patients with AML beyond existing risk factors. Furthermore, we found low expression levels of LDLR in most healthy tissues, suggesting it as a promising target for antibody‐based pharmacodelivery approaches in AML. [ABSTRACT FROM AUTHOR]

Considering the unsatisfactory results of salvage therapies for patients with relapsed/refractory acute myeloid leukaemia (R/R-AML), their value before allogeneic haematopoietic stem cell transplantation (HSCT) remains questionable. However, direct allogeneic HSCT following established conditioning regimens applied in patients with R/R-AML during active disease has been equally disappointing. In this retrospective observational study, highdose melphalan, as part of a sequential preparative regimen, followed by a total body irradiation (4 × 2 Gy)-based or a treosulfan-based dose-adapted conditioning therapy for allogeneic HSCT was administered to 292 adult patients (median age 56 years, range 17-74) with primary refractory (144 patients), secondary refractory (97 patients) or relapsed AML (51 patients). Overall survival rates at 3 years were 34%, 29% and 41%, respectively. Risk factors associated with an inferior survival were higher age, transplantation from a human leucocyte antigen-mismatched donor and high disease burden. Patients transplanted with blast infiltration <20% showed a notable survival rate of 51% at 3 years. In particular, patients with primary refractory AML showed a more favourable outcome when transplanted early during their disease course. Thus, high-dose melphalan-based sequential conditioning chemotherapy followed by an allogeneic HSCT is feasible and enables long-term remission to be achieved in a substantial proportion of patients with active R/R-AML. [ABSTRACT FROM AUTHOR]

Nintedanib (BIBF 1120), a potent multikinase inhibitor of VEGFR-1/-2/-3, FGFR-1/-2/-3 and PDGFR-α/-β, exerts growth inhibitory and pro-apoptotic effects in myeloid leukemic cells, especially when used in combination with cytarabine. This phase I study evaluated nintedanib in combination with low-dose cytarabine (LDAC) in elderly patients with untreated or relapsed/refractory acute myeloid leukemia (AML) ineligible for intensive chemotherapy in a 3+3 design. Nintedanib (dose levels 100, 150, and 200 mg orally twice daily) and LDAC (20 mg subcutaneous injection twice daily for 10 days) were administered in 28-day cycles. Dose-limiting toxicity (DLT) was defined as non-hematological severe adverse reaction CTC grade ≥ 4 with possible or definite relationship to nintedanib. Between April 2012 and October 2013, 13 patients (median age 73 [range: 62–86] years) were enrolled. One patient did not receive study medication and was replaced. Nine (69%) patients had relapsed or refractory disease and 6 (46%) patients had unfavorable cytogenetics. The most frequently reported treatment-related adverse events (AE) were gastrointestinal events. Twelve SAEs irrespective of relatedness were reported. Two SUSARs were observed, one fatal hypercalcemia and one fatal gastrointestinal infection. Two patients (17%) with relapsed AML achieved a complete remission (one CR, one CRi) and bone marrow blast reductions without fulfilling PR criteria were observed in 3 patients (25%). One-year overall survival was 33%. Nintedanib combined with LDAC shows an adequate safety profile and survival data are promising in a difficult-to-treat patient population. Continuation of this trial with a phase II recommended dose of 2 x 200 mg nintedanib in a randomized, placebo-controlled phase II study is planned. The trial is registered to EudraCT as 2011-001086-41. Trial Registration: ClinicalTrials.gov [ABSTRACT FROM AUTHOR]

Background: This retrospective, multicenter study aimed to reveal risk predictors for mortality in the intensive care unit (ICU) as well as survival after ICU discharge in patients with acute myeloid leukemia (AML) requiring treatment in the ICU. Methods and Results: Multivariate analysis of data for 187 adults with AML treated in the ICU in one institution revealed the following as independent prognostic factors for death in the ICU: arterial oxygen partial pressure below 72 mmHg, active AML and systemic inflammatory response syndrome upon ICU admission, and need for hemodialysis and mechanical ventilation in the ICU. Based on these variables, we developed an ICU mortality score and validated the score in an independent cohort of 264 patients treated in the ICU in three additional tertiary hospitals. Compared with the Simplified Acute Physiology Score (SAPS) II, the Logistic Organ Dysfunction (LOD) score, and the Sequential Organ Failure Assessment (SOFA) score, our score yielded a better prediction of ICU mortality in the receiver operator characteristics (ROC) analysis (AUC = 0.913 vs. AUC = 0.710 [SAPS II], AUC = 0.708 [LOD], and 0.770 [SOFA] in the training cohort; AUC = 0.841 for the developed score vs. AUC = 0.730 [SAPSII], AUC = 0.773 [LOD], and 0.783 [SOFA] in the validation cohort). Factors predicting decreased survival after ICU discharge were as follows: relapse or refractory disease, previous allogeneic stem cell transplantation, time between hospital admission and ICU admission, time spent in ICU, impaired diuresis, Glasgow Coma Scale <8 and hematocrit of ≥25% at ICU admission. Based on these factors, an ICU survival score was created and used for risk stratification into three risk groups. This stratification discriminated distinct survival rates after ICU discharge. Conclusions: Our data emphasize that although individual risks differ widely depending on the patient and disease status, a substantial portion of critically ill patients with AML benefit from intensive care. [ABSTRACT FROM AUTHOR]

Overweight and obese patients have an increased risk to develop several malignancies and, additionally, body mass index ( BMI) impacts on outcome in several solid tumors. However, little is known for AML. We analyzed a cohort of 3526 patients with AML treated in three prospective multicenter trials within the German Study Alliance Leukemia. In multivariate analyses, we identified BMI as an independent risk factor for both DFS ( HR 1.014, P = 0.0217) and OS ( HR 1.015, P < 0.0036). Interestingly, overweight and obesity seemed to be a risk factor predominantly in patients with de novo AML younger than 65 yr with intermediate risk and adverse cytogenetics. Overweight with a BMI ≥25 kg/m² best discriminated the worse outcome and led to an absolute reduction in long-term survival of 5-7% in the group of all younger patients (3-yr OS 39.9% vs. 47.3%; 10-yr OS 28.7% vs. 33.8%, P = 0.0002). Additionally, response to induction therapy was significantly reduced in these patients (76.9% vs. 82.8%, P < 0.0001). Thus, in younger patients with de novo AML, overweight and obesity are risk factors for impaired response to induction therapy, DFS and OS. This effect is, in part but not fully, explained by dose reduction such as dose-capping at a body surface area of 2 m². [ABSTRACT FROM AUTHOR]

Treatment success in patients with acute myeloid leukaemia ( AML) is heterogeneous. Cytogenetic and molecular alterations are strong prognostic factors, which have been used to individualize treatment. Here, we studied the impact of TP53 mutations on the outcome of AML patients with adverse cytogenetic risk treated with allogeneic haematopoietic stem cell transplantation ( HSCT). Samples of 97 patients with AML and adverse-risk cytogenetics who had received a HSCT within three randomized trials were analysed. Complete sequencing of the TP53 coding region was performed using next generation sequencing. The median age was 51 years. Overall, TP53 mutations were found in 40 patients (41%). With a median follow up of 67 months, the three-year probabilities of overall survival ( OS) and event-free survival for patients with TP53 wild type were 33% [95% confidence interval ( CI), 21% to 45%] and 24% (95% CI, 13% to 35%) compared to 10% (95% CI, 0% to 19%) and 8% (95% CI, 0% to 16%) ( P = 0·002 and P = 0·007) for those with mutated TP53, respectively. In multivariate analysis, the TP53-mutation status had a negative impact on OS (Hazard Ratio = 1·7; P = 0·066). Mutational analysis of TP53 might be an important additional tool to predict outcome after HSCT in patients with adverse karyotype AML. [ABSTRACT FROM AUTHOR]

The adapter protein metastasis suppressor 1 (MTSS1) is implicated as a tumor suppressor or tumor promoter, depending on the type of solid cancer. Here, we identified Mtss1 expression to be increased in AML subsets with favorable outcome, while suppressed in high risk AML patients. High expression of MTSS1 predicted better clinical outcome of patients with normal-karyotype AML. Mechanistically, MTSS1 expression was negatively regulated by FLT3-ITD signaling but enhanced by the AML1-ETO fusion protein. DNMT3B, a negative regulator of MTSS1, showed strong binding to the MTSS1 promoter in PML-RARA positive but not AML1-ETO positive cells, suggesting that AML1-ETO leads to derepression of MTSS1. Pharmacological treatment of AML cell lines carrying the FLT3-ITD mutation with the specific FLT3 inhibitor PKC-412 caused upregulation of MTSS1. Moreover, treatment of acute promyelocytic cells (APL) with all-trans retinoic acid (ATRA) increased MTSS1 mRNA levels. Taken together, our findings suggest that MTSS1 might have a context-dependent function and could act as a tumor suppressor, which is pharmacologically targetable in AML patients. [ABSTRACT FROM AUTHOR]

Functional differences between healthy progenitor and cancer initiating cells may provide unique opportunities for targeted therapy approaches. Hematopoietic stem cells are tightly controlled by a network of CDK inhibitors that govern proliferation and prevent stem cell exhaustion. Loss of Inca1 led to an increased number of short-term hematopoietic stem cells in older mice, but Inca1 seems largely dispensable for normal hematopoiesis. On the other hand, Inca1-deficiency enhanced cell cycling upon cytotoxic stress and accelerated bone marrow exhaustion. Moreover, AML1-ETO9a-induced proliferation was not sustained in Inca1-deficient cells in vivo. As a consequence, leukemia induction and leukemia maintenance were severely impaired in Inca1−/− bone marrow cells. The re-initiation of leukemia was also significantly inhibited in absence of Inca1−/− in MLL—AF9- and c-myc/BCL2-positive leukemia mouse models. These findings indicate distinct functional properties of Inca1 in normal hematopoietic cells compared to leukemia initiating cells. Such functional differences might be used to design specific therapy approaches in leukemia. [ABSTRACT FROM AUTHOR]

NPM1 mutations represent frequent genetic alterations in patients with acute myeloid leukemia (AML) associated with a favorable prognosis. Different types of NPM1 mutations have been described. The purpose of our study was to evaluate the relevance of different NPM1 mutation types with regard to clinical outcome. Our analyses were based on 349 NPM1-mutated AML patients treated in the AMLCG99 trial. Complete remission rates, overall survival and relapse-free survival were not significantly different between patients with NPM1 type A or rare type mutations. The NPM1 mutation type does not seem to play a role in risk stratification of cytogenetically normal AML. [ABSTRACT FROM AUTHOR]

External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1−/− hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1−/− leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance. [ABSTRACT FROM AUTHOR]

Acute myeloid leukaemia ( AML) is a heterogenous disease. Prognosis of AML is influenced both by patient-specific as well as disease-specific factors. Age is the most prominent patient-specific risk factor, while chromosomal aberrations are the strongest disease-specific risk factors. For patients with cytogenetically normal AML, prognosis can be specified by mutational status of the genes NPM1, FLT3 and CEBPA. A growing number of recurrent mutations in additional genes have recently been identified, for which the prognostic effect yet has to be determined. Performance status, geriatric assessment, secondary leukaemia following myelodysplastic syndrome or cytotoxic treatment, common laboratory parameters, leukaemic stem cell frequency, bone marrow microenvironment, gene expression levels, epigenetic changes, micro- RNA's as well as kinetics and depth of response to treatment influence prognosis of AML patients. Despite the high number of established risk factors, only few predictive markers exist which can truly aid therapy decisions in patients with AML. [ABSTRACT FROM AUTHOR]

About 30% of patients with acute myeloid leukemia (AML) harbour mutations of the receptor tyrosine kinase FLT3, mostly internal tandem duplications (ITD) and point mutations of the second tyrosine kinase domain (TKD). It was the aim of this study to comprehensively analyze clinical and functional properties of various FLT3 mutants. In 672 normal karyotype AML patients FLT3-ITD, but not FLT3-TKD mutations were associated with a worse relapse free and overall survival in multivariate analysis. In paired diagnosis-relapse samples FLT3-ITD showed higher stability (70%) compared to FLT3-TKD (30%). In vitro, FLT3-ITD induced a strong activating phenotype in Ba/F3 cells. In contrast, FLT3-TKD mutations and other point mutations – including two novel mutations – showed a weaker but clear gain-of-function phenotype with gradual increase in proliferation and protection from apoptosis. The pro-proliferative capacity of the investigated FLT3 mutants was associated with cell surface expression and tyrosine 591 phosphorylation of the FLT3 receptor. Western blot experiments revealed STAT5 activation only in FLT3-ITD positive cell lines, in contrast to FLT3-non-ITD mutants, which displayed an enhanced signal of AKT and MAPK activation. Gene expression analysis revealed distinct difference between FLT3-ITD and FLT3-TKD for STAT5 target gene expression as well as deregulation of SOCS2, ENPP2, PRUNE2 and ART3. FLT3-ITD and FLT3 point mutations show a gain-of-function phenotype with distinct signalling properties in vitro. Although poor prognosis in AML is only associated with FLT3-ITD, all activating FLT3 mutations can contribute to leukemogenesis and are thus potential targets for therapeutic interventions. [ABSTRACT FROM AUTHOR]

Polo-like kinases (Plks) play an important role in cell cycle checkpoint controls and are over-expressed in acute myeloid leukaemia ( AML). BI 2536, a novel Plk inhibitor, induces mitotic arrest and apoptosis. In this phase I/II trial of BI 2536 in 68 elderly patients with relapsed/refractory AML, three schedules were investigated (day 1, days 1-3, and days 1 + 8). Maximum tolerated dose was 350 and 200 mg in the day 1 and days 1 + 8 schedules, respectively. The day 1-3 schedule appeared equivalent to the day 1 schedule and was discontinued early. BI 2536 exhibited multi-compartmental pharmacokinetic behaviour. The majority of patients showed an increase of bone marrow cells in G2/M with a characteristic pattern of mitotic catastrophe. The overall response rate in the day 1 and day 1 + 8 schedules was 9% (5/54) with 2 complete and 3 partial responses. The majority of drug-related adverse events grade ≥3 were haematological. Taken together, Plk inhibition induced cell cycle arrest in AML blasts in vivo and BI 2536 monotherapy showed modest clinical activity in this poor prognosis patient group. [ABSTRACT FROM AUTHOR]

Sorafenib is a multi-kinase inhibitor with activity against several intracellular kinases which may play a role in the pathogenesis of acute myeloid leukemia (AML). In vitro data and results from early clinical trials suggest that sorafenib might be an effective drug for the treatment of AML. However, clinical data are still sparse, and there are only a few reported cases of monotherapy. The aim of the present research was to collect clinical data on efficacy and safety in a systematic way by conducting a survey on clinical experience with sorafenib. Thirty institutions were asked to document all patients treated with sorafenib diagnosed with AML. Of all 29 evaluable patients, six (21%) responded to sorafenib containing treatment by achieving a complete remission (CR, n = 2) or complete remission with incomplete platelet recovery (CRi, n = 4). In 23 patients receiving sorafenib as monotherapy, the CRi rate amounted to 13% and no CRs were documented. Of the 18 FLT-ITD positive patients with sorafenib monotherapy, two patients achieved a CRi (11%). In five FLT3-ITD negative cases, one CRi was documented (20%). Our results suggest the potential ability of the drug to induce remissions in refractory or relapsed AML even when given as monotherapy. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) play an important role in cellular differentiation and cancer pathogenesis. This study analysed the expression of 154 human miRNAs in acute myeloid leukaemia (AML) and control samples using a stem-loop real-time reverse transcription polymerase chain reaction approach. Global patterns of miRNA expression in AML, normal bone marrow (NBM) and CD34+ progenitor cells allowed correct class predictions similar to whole genome microarray expression analyses that were performed at the same time. At single miRNA species level, MIRN23B was repressed in AML specimens compared to NBM and purified CD34+ haematopoietic progenitor cells. In contrast, the MIRN221/MIRN222 cluster and MIRN34A were expressed at significantly higher levels in AML blasts. Patients with high MIRN221/MIRN222 expression showed low levels of KIT RNA and protein expression but the correlation between kit protein and KIT mRNA was significantly stronger than the correlation of either one with MIRN221/MIRN222. A global analysis between miRNA expression levels and mRNA expression of predicted target genes revealed only weak associations in the majority of miRNA species. Nonetheless, the presence of two or more miRNA binding sites within the mRNA was usually associated with a decrease in mRNA levels. Taken together, these findings provide evidence that specific miRNA expression patterns exist in AML. [ABSTRACT FROM AUTHOR]

Background: The identification of suitable patients is a common problem in clinical trials that is especially evident in tertiary care hospitals. Methods: We developed and analysed a workflow, which uses routine data captured during patient care in a hospital information system (HIS), to identify potential trial subjects. Study nurses or physicians are notified automatically by email and verify eligibility. Results: As a case study we implemented the system for acute myeloid leukemia (AML) trials in Münster. During a test period of 50 days 41 patients were identified by the system. 13 could be included as new trial patients, 7 were already included during earlier visits. According to review of paper records no AML trial patient was missed by the system. In addition, the hospital information system further allowed to preselect patients for specific trials based on their disease status and individual characteristics. Conclusion: Routine HIS data can be used to support patient recruitment for clinical trials by means of an automated notification workflow. [ABSTRACT FROM AUTHOR]

Maintenance treatment for AML is an approach to minimize residual disease, optimize quality of remission and prevent a leukemic regrowth over a longer period of time. This intention implies a certain antileukemic activity and myelotoxicity. Thus, a prolonged myelosuppressive maintenance is best exemplified by the optimized protocol of the CALGB published by Kanti R. Rai in 1981 (Blood 58:1203-1212, 1981) and derived by the AMLCG as a therapeutic standard. From our today's knowledge about the impact of various strategies, a lack of postremission therapy is not compatible with durable remissions. Even after an induction-type consolidation, the classic CALGB-type maintenance, or a comparably intensive regimen improved the relapse-free survival over that from alternatives. Some studies which failed to show a benefit used maintenance at low-dosage or short duration. Data about maintenance delivery in patients reaching long-term remissions demonstrate feasibility and compliance, and a low maintenance-related death rate can compete with that from alternative options. Revisiting maintenance, however, requires a comparison with other strategies on the basis of intention-to-treat. Either single prospective trials or crosstrial networking by a common standard arm and general upfront randomization can further assess the relative value of maintenance for AML. [ABSTRACT FROM AUTHOR]

Abstract: Undertreatment of the older patients with AML can explain, in part, their inferior outcome when compared with that in younger patients. In analogy to the benefit of patients under the age of 60 years from high-dose AraC there are dosage related therapeutic effects in the patients over 60 years in particular for daunorubicin in the induction treatment, and for maintenance versus no maintenance in the post-remission treatment. Utilizing these effects can partly overcome the mostly unfavorable disease biology in older age AML, whereas the role of risk factors involved is not completely understood and the concept of dose–response needs to be requestioned. We recommend an adequate dosage of 60mg/(m2 day) daunorubicin for 3 days in a combination with standard dose AraC and 6-thioguanine given for induction and consolidation and followed by a prolonged monthly maintenance chemotherapy. Further improvements in supportive care may help delivering additional anti-leukemic cytotoxicity. As a novel approach, reduced toxicity preparative regimens may open up allogeneic transplantation for older patients with AML. Other new options like MDR modulators, antibody targeted therapies and tyrosine kinase inhibitors are under clinical investigation. A questionnaire study in patients with AML showed that according to patients’ self-assessment intensive and prolonged treatment did not result in decreasing quality of life. This finding did not vary by age under or above 60 years. Given the actual median age in this disease being more than 60 years the adequate management of older age AML remains as the major challenge. [Copyright &y& Elsevier]

Studies the treatment of acute myelocytic leukemia in biological subgroups. Response of the disease to chemotherapy by a remission; Abnormalities associated with poor prognosis; Requirement for novel approaches including allogeneic stem cell transplantation at optimized conditioning.

The acute myeloid leukemia (AML)-associated translocation products AML1-ETO, PML-retinoic acid receptor alpha (RARα), and PLZF-RARα encode aberrant transcription factors. Several lines of evidence suggest similar pathogenetic mechanisms for these fusion proteins. We used high-density oligonucleotide arrays to identify shared target genes in inducibly transfected U937 cells expressing AML1.ETO, PML-RARα, or PLZF-RARα. All three fusion proteins significantly repressed the expression of 38 genes and induced the expression of 14 genes. Several of the regulated genes were associated with Wnt signaling. One of these, plakoglobin (γ-catenin), was induced on the mRNA and protein level by all three fusion proteins. In addition, primary AML blasts carrying one of the fusion proteins significantly overexpressed plakoglobin. The plakoglobin promoter was cloned and shown to be induced by AML1-ETO, with promoter activation depending on the corepressor and histone deacetylase binding domains. The induction of plakoglobin by AML fusion proteins led to downstream signaling and transactivation of TCF- and LEF-dependent promoters, including the c-myc promoter, which was found to be bound by plakoglobin in vivo after AML1-ETO expression. β-Catenin protein levels and TCF and LEF target genes such as c-myc and cyclin D1 were found to be induced by the fusion proteins. On the functional level, a dominant negative TCF inhibited colony growth of AML1-ETO-positive Kasumi cells, whereas plakoglobin transfection into myeloid 32D cells enhanced proliferation and clonal growth. Injection of plakoblobin-expressing 32D cells into syngeneic mice accelerated the development of leukemia. Transduction of plakoglobin into primitive murine hematopoietic progenitor cells preserved the immature phenotype during colony growth, suggesting enhanced self-renewal. These data provide evidence that activation of Wnt signaling is a common feature of several balanced translocation in AML. [ABSTRACT FROM AUTHOR]

Cytogenetic data have significantly contributed to our understanding of the heterogeneity of acute myeloid leukemia (AML). In AML, numerous recurrent chromosomal aberrations have been identified, and several of them, e.g. t(8;21)(q22;q22), t(15;17)(q22;q11-12), inv(16)(p13q22), are specific for distinct subgroups. Furthermore, chromosomal aberrations have proved to be of paramount prognostic importance for remission induction and survival. Chromosome analysis using classical cytogenetic banding techniques often fails to completely resolve complex karyotypes and cryptic translocations not identifiable by these techniques have been detected using molecular cytogenetic methods. While fluorescence in situ hybridization (FISH) has become an indispensable tool for screening and follow-up of known aberrations, the techniques of spectral karyotyping (SKY) and multiplex-fluorescence in situ hybridization (M-FISH) allow for the simultaneous visualization of all chromosomes of a metaphase in a single hybridization step, and thereby enable screening for the aberrations present without their prior knowledge. Therefore, with the introduction of these techniques in 1996 the comprehensive analysis of complex karyotypes and the identification of new, hitherto cryptic translocations and, ultimately, the identification of new disease subgroups seemed possible. Since, more than 600 cases of AML and MDS have been analyzed. Herein, we attempt to summarize the data published and discuss what has been achieved towards realization of these goals. [ABSTRACT FROM AUTHOR]

The t(8;21) is one of the most frequent chromosomal translocations associated with acute leukemia. This translocation creates a fusion protein consisting of the acute myeloid leukemia-1 transcription factor and the eight-twenty-one corepressor (AML1?ETO), which represses transcription through AML1 (RUNX1) DNA binding sites and immortalizes hematopoietic progenitor cells. We have identified the p14ARF tumor suppressor, a mediator of the p53 oncogene checkpoint, as a direct transcriptional target of AML1?ETO. AML1?ETO repressed the p14ARF promoter and reduced endogenous levels of p14ARF expression in multiple cell types. In contrast, AML1 stimulated p14ARF expression and induced phenotypes consistent with cellular senescence. Chromatin immunoprecipitation assays demonstrated that AML1?ETO was specifically bound to the p14ARF promoter. In acute myeloid leukemia samples containing the t(8;21), levels of p14ARF mRNA were markedly lower when compared with other acute myeloid leukemias lacking this translocation. Repression of p14ARF may explain why p53 is not mutated in t(8;21)-containing leukemias and suggests that p14ARF is an important tumor suppressor in a large number of human leukemias. [ABSTRACT FROM AUTHOR]

Smoking is a well-established risk factor for cancers of the lung, head and neck; nasopharynx; upper digestive tract (esophagus, stomach, liver, pancreas); kidney; bladder; cervix; and for acute myeloid leukaemia (AML).1 Growing evidence also point towards a history of smoking, or being a current smoker, as a risk factor for decreased survival after diagnosis in a variety of cancers.2 In this issue, Kristensen I et al. i demonstrate a decreased overall survival for current smokers, or patients with a history of smoking, compared to never smokers in >1,000 patients who have been diagnosed with AML and received an intensive chemotherapy for remission induction. Overall, this study and others provide a strong indication that smoking not only influences the incidence of AML, but also the prognosis after AML diagnosis, even when patients are receiving uniform AML treatment. Due to the nature of retrospective correlative studies, it cannot be determined whether the inferior prognosis of patients with a smoking history is attributable to a more aggressive AML biology or to patient-related factors, such as an increased toxicity of AML treatment. [Extracted from the article]

Flow cytometry was applied to test for platelet-activating-factor receptor (PAF-R) presence on the membranes of acute myeloid leukemia (AML) cells. We have used six human AML cell lines and freshly taken density gradient separated blasts from the bone marrow of ten AML patients covering the majority of French–American–British (FAB) subtypes. Additionally, we have used one histiocytic lymphoma cell line and mature human granulocytes/monocytes as controls. Our results indicate lack of membrane PAF-R on AML of all FAB subtypes tested. This was particularly true for the more mature and differentiated subtypes M4 and M5, including monocytic cell elements, and the promyelocytic M3 AML. In contrast, membrane PAF-R could be easily detected in a histiocytic lymphoma cell line and mature granulocytes/monocytes from peripheral blood used as positive controls. In conclusion, this observation precludes the use of membrane PAF-R as an immunophenotypic marker for AML classification or detection of minimal residual disease. [ABSTRACT FROM AUTHOR]

Most persons age ≥60 y with acute myeloid leukaemia (AML) die from their disease. When interpreting clinical trials data from these persons one must be aware of substantial selection biases. Randomized trials of post-remission treatments can be performed upfront or after achieving defined landmarks. Both strategies have important limitations. Selection of the appropriate treatment is critical. Age, performance score, co-morbidities and frailty provide useful data to treatment selection. If an intensive remission induction therapy is appropriate, therapy with cytarabine and an anthracycline is the most common regimen. Non-intensive therapies consist of the hypo-methylating drugs azacitidine and decitabine, low-dose cytarabine and supportive care. Feasibility of doing an allotransplant in older persons with AML is increasing. However, only very few qualify. Results of cytogenetic testing are risk factor in young and old persons with AML. Adverse abnormalities are more frequent in older persons. Although data about the frequency of mutations in older persons with AML is increasing their prognostic impact is less clear than in younger subjects. Neither differences in the distribution of cytogenetic risk, mutations, nor differences in clinical risk factors between younger and older persons with AML completely explain the age-dependent outcome. Many drugs are in clinical development in older persons with AML. Their potential role in the treatment of older persons with AML remains to be defined. [ABSTRACT FROM AUTHOR]

The clinical and prognostic relevance of many recently identified driver gene mutations in adult acute myeloid leukemia (AML) is poorly defined. We sequenced the coding regions or hotspot areas of 68 recurrently mutated genes in a cohort of 664 patients aged 18 to 86 years treated on 2 phase 3 trials of the German AML Cooperative Group (AMLCG). The median number of 4 mutations per patient varied according to cytogenetic subgroup, age, and history of previous hematologic disorder or antineoplastic therapy. We found patterns of significantly comutated driver genes suggesting functional synergism. Conversely, we identified 8 virtually nonoverlapping patient subgroups, jointly comprising 78% of AML patients, that are defined by mutually exclusive genetic alterations. These subgroups, likely representing distinct underlying pathways of leukemogenesis, show widely divergent outcomes. Furthermore, we provide detailed information on associations between gene mutations, clinical patient characteristics, and therapeutic outcomes in this large cohort of uniformly treated AML patients. In multivariate analyses including a comprehensive set of molecular and clinical variables, we identified DNMT3A and RUNX1 mutations as important predictors of shorter overall survival (OS) in AML patients <60 years, and particularly in those with intermediate-risk cytogenetics. NPM1 mutations in the absence of FLT3-ITD, mutated TP53, and biallelic CEBPA mutations were identified as important molecular prognosticators of OS irrespective of patientage. Insummary, our study provides a comprehensive overview of the spectrum, clinical associations, and prognostic relevance of recurrent driver gene mutations in a large cohort representing a broad spectrum and age range of intensively treated AML patients. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic cell transplantation (alloHCT) as a postremission therapy in patients with FLT3-ITD –positive intermediate-risk acute myeloid leukemia (AML) remains controversial. FLT3-ITD mutations are heterogeneous with respect to allelic ratio, location, and length of the insertion, with a high mutant-to-wild-type ratio consistently associated with inferior prognosis. We retrospectively analyzed the role of alloHCT in first remission in relationship to the allelic ratio and presence or absence of nucleophosmin 1 mutations ( NPM1 ) in the Study Alliance Leukemia AML2003 trial. FLT3-ITD mutations were detected in 209 patients and concomitant NPM1 mutations in 148 patients. Applying a predefined cutoff ratio of .8, AML was grouped into high- and low-ratio FLT3-ITD AML (HR FLT3-ITD and LR FLT3-ITD ). Sixty-one patients (29%) were transplanted in first remission. Overall survival (OS) (HR, .3; 95% CI, .16 to .7; P = .004) and event-free survival (EFS) (HR, .4; 95% CI, .16 to .9; P = .02) were significantly increased in patients with HR FLT3-ITD AML who received alloHCT as consolidation treatment compared with patients who received consolidation chemotherapy. Patients with LR FLT3-ITD AML and wild-type NPM1 who received alloHCT in first remission had increased OS (HR, .3; 95% CI, .1 to .8; P = .02) and EFS (HR, .2; 95% CI, .1 to .8; P = .02), whereas alloHCT in first remission did not have a significant impact on OS and EFS in patients with LR FLT3-ITD AML and concomitant NPM1 mutation. In conclusion, our results provide additional evidence that alloHCT in first remission improves EFS and OS in patients with HR FLT3-ITD AML and in patients with LR FLT3-ITD AML and wild-type NPM1 . [ABSTRACT FROM AUTHOR]

The transcription factor Myb plays a key role in the hematopoietic system and has been implicated in the development of leukemia and other human cancers. Inhibition of Myb is therefore emerging as a potential therapeutic strategy for these diseases. However, because of a lack of suitable inhibitors, the feasibility of therapeutic approaches based on Myb inhibition has not been explored. We have identified the triterpenoid Celastrol as a potent low-molecular-weight inhibitor of the interaction of Myb with its cooperation partner p300. We demonstrate that Celastrol suppresses the proliferative potential of acute myeloid leukemia (AML) cells while not affecting normal hematopoietic progenitor cells. Furthermore, Celastrol prolongs the survival of mice in a model of an aggressive AML. Overall, our work demonstrates the therapeutic potential of a small molecule inhibitor of the Myb/p300 interaction for the treatment ofAMLandprovides a starting point for the furtherdevelopment of Myb-inhibitorycompoundsfor the treatment of leukemia and, possibly, other tumors driven by deregulated Myb. [ABSTRACT FROM AUTHOR]

In acute myeloid leukemia (AML), isolated trisomy 13 (AML+13) is a rare chromosomal abnormality whose prognostic relevance is poorly characterized. We analyzed the clinical course of 34 AML+13 patients enrolled in the German AMLCG-1999 and SAL trials and performed exome sequencing, targeted candidate gene sequencing and gene expression profiling. Relapse-free (RFS) and overall survival (OS) of AML+13 patients were inferior compared to other ELN Intermediate-ll patients (n=855) (median RFS, 7.8 vs 14.1 months, P = .006; median OS 9.3 vs. 14.8 months, P = .004). Besides the known high frequency of RUNX1 mutations (75%), we identified mutations in spliceosome components in 88%, including SRSF2 codon 95 mutations in 81%. Recurring mutations were detected in ASXL 7(44%) and BCOR(25%). Two patients carried mutations in CEBPZ, suggesting that CEBPZ is a novel recurrently mutated gene in AML. Gene expression analysis revealed a homogeneous expression profile including upregulation of FOXOI and FLT3 and downregulation of SPRY2. This is the most comprehensive clinical and biological characterization of AML+13 to date, and reveals a striking clustering of lesions in a few genes, defining AML+13 as a genetically homogeneous subgroup with alterations in a few critical cellular pathways. Clinicaltrials.gov identifiers; AMLCG-1999: NCT00266136; AML96: NCT00180115; AML2003: NCT00180102; and AML60+: NCT00893373 (Blood. 2014; 124(8): 1304-1311) [ABSTRACT FROM AUTHOR]

The t(8;21) and inv(16)/t(16;16) rearrangements affecting the core-binding factors RUNX1 and CBFB, respectively, are found.in 15% to 20% of adult de novo acute myeloid leukemia (AML) cases and are associated with a favorable prognosis. Since the expression of the fusion genes CBFBIMYH11 or RUNX1IRUNX1T1 alone is not sufficient to cause leukemia, we performed exome sequencing of an AML sample with an inv(16) to identify mutations, which may collaborate with the CBFB/MYH11 fusion during leukemogenesis. We discovered an N676K mutation in the adenosine triphosphate (ATP)-binding domain (tyrosine kinase domain 1 [TKD1]) of the fms-related tyrosine kinase 3 (FLT3) gene. In a cohort of 84 de novo AML patients with a CBFB/MYH11 rearrangement and in 36 patients with a RUNX1/RUNX1T1 rearrangement, the FLT3 N676K mutation was identified in 5 and 1 patients, respectively (5 [6%] of 84; 1 [3%] of 36). The FLT3-N676K mutant alone leads to factor-independent growth in Ba/F3 cells and, together with a concurrent FLT3- ITD (internal tandem duplication), confers resistance to the FLT3 protein tyrosine kinase inhibitors (PTKIs) PKC412 and AC220. Gene expression analysis of AML patients with CBFBIMYH11 rearrangement and FLT3 N676K mutation showed a trend toward a specific expression profile. Ours is the first report of recurring FLT3 N676 mutations in core-binding factor (CBF) leukemias and suggests a defined subgroup of CBF leukemias. [ABSTRACT FROM AUTHOR]

Summary: Background: Reduced-intensity conditioning regimens have been developed to minimise early toxic effects and deaths after allogeneic haemopoietic cell transplantation. However, the efficacy of these regimens before this procedure has not been investigated in a randomised trial. In this prospective, open-label randomised phase 3 trial we compared a reduced-intensity fludarabine-based conditioning regimen with a standard regimen in patients with acute myeloid leukaemia in first complete remission. Methods: Patients were aged 18–60 years and had intermediate-risk or high-risk acute myeloid leukaemia (defined by cytogenetics) in first complete remission; an available HLA-matched sibling donor or an unrelated donor with at least nine of ten HLA alleles; and adequate renal, cardiac, pulmonary, and neurological function. Between Nov 15, 2004, and Dec 31, 2009, patients were randomly assigned (1:1, by a computer-based minimisation procedure that balanced patients for age, cytogenetic risk, induction therapy, and donor type) to receive either reduced-intensity conditioning of four doses of 2 Gy of total-body irradiation and 150 mg/m2 fludarabine or standard conditioning of six doses of 2 Gy of total-body irradiation and 120 mg/kg cyclophosphamide. All patients were given ciclosporin and methotrexate as prophylaxis against graft-versus-host disease. Neither investigators nor patients were blinded to study treatment. Our primary endpoint was the incidence of non-relapse mortality, analysed in the intention-to-treat population. The trial is registered with ClinicalTrials.gov, number NCT00150878. Findings: The trial was stopped early on Dec 31, 2009, because of slow accrual of patients. 99 patients were randomly assigned to receive reduced-intensity conditioning and 96 to receive standard conditioning. The incidence of non-relapse mortality did not differ between the reduced-intensity and standard conditioning groups (cumulative incidence at 3 years 13% [95% CI 6–21] vs 18% [10–26]; HR 0·62 [95% CI 0·30–1·31]). Relapse incidence (cumulative incidence 3 years 28% [95% CI 19–38] vs 26% [17–36]; HR 1·10 [95% CI 0·63–1·90]), disease-free survival (3 year disease-free survival 58% [95% CI 49–70] vs 56% [46–67]; HR 0·85 [95% CI 0·55–1·32]), and overall survival (3 year overall survival 61% [95% CI 50–74] vs 58% [47–70]; HR 0·77 [95% CI 0·48–1·25]) did not differ significantly between groups. Grade 3–4 of oral mucositis was less common in the reduced-intensity group than in the standard conditioning group (50 patients in the reduced-intensity conditioning group vs 73 patients in the standard conditioning group); the frequency of other side-effects such as graft-versus-host disease and increased concentrations of bilirubin and creatinine did not differ significantly between groups. Interpretation: Reduced-intensity conditioning results in a similar incidence of non-relapse mortality and reduced toxic effects compared with standard conditioning without affecting survival outcomes, and thus could be preferentially used in patients younger than 60 years with acute myeloid leukaemia transplanted in first complete remission. Funding: Medical Faculty of Dresden University. [Copyright &y& Elsevier]

Osteopontin (OPN) is a glycoprotein that is secreted by osteoblasts and hematopoietic cells. OPN suppresses the proliferation of hematopoietic stem cells in vitro and may regulate the hematopoietic stem cell pool. Increased serum OPN concentrations occur in chronic myeloid leukemia, multiple myeloma, and acute myeloid leukemia (AML). In the present study, we analyzed the prognostic impact of OPN in AML by investigating the expression and relevance of OPN in newly diagnosed AML patients from 2 large study groups (the German AML Cooperative Group and the Dutch-Belgian Hematology Oncology Cooperative group). IHC (n = 84), ELISAs of blood/BM sera (n = 41), and microarray data for mRNA levels (n = 261) were performed. Expression of OPN protein was increased in AML patients both in BM blasts (IHC) and in BM serum (ELISA) compared with healthy controls. Patients expressing high levels of OPN within the BM (IHC) experienced shortened overall survival (OS; P = .025). Multivariate analysis identified karyotype, blast clearance (day 16), and the level of OPN expression as independent prognostic factors for OS. This prompted us to analyze microarray data from 261 patients from a third cohort. The analysis confirmed OPN as a prognostic marker. In summary, high OPN mRNA expression indicated decreased event-free survival (P = .0002) and OS (P=.001). The prognostic role of OPN was most prominent in intermediate-risk AML. These data provide evidence that OPN expression is an independent prognostic factor in AML. [ABSTRACT FROM AUTHOR]

Abstract: Epigenetic changes play a crucial role in leukemogenesis. HDACs are frequently recruited to target gene promoters by balanced translocation derived oncogenic fusion proteins. As important epigenetic effector mechanisms, histone deacetylases (HDAC) have emerged as potential therapeutic targets. However, the patterns of HDAC1 localization and the role of HDACs in leukemia pathogenesis remain to be elucidated. Using ChIP-Chip analyses we analyzed HDAC1 deposition patterns at more than 10,000 gene promoters in a large cohort of leukemia patients and CD34+ controls. HDAC1 binding was significantly increased in AML blasts compared to CD34+ progenitor cells at 130 gene promoters whereas decreased binding was observed at 66 gene promoters. Distinct HDAC1 binding patterns occurred in AML subtypes with balanced translocations t(15;17), t(8;21) and inv(16). In addition, a more generalized signature was established, that revealed an AML specific pattern of HDAC1 distribution. Many of the HDAC1-binding altered promoters regulate genes involved in hematopoiesis, transcriptional regulation and signal transduction. HDAC1 binding patterns were associated with patients’ event free survival. This is the first study to determine HDAC1 modification patterns in a large number of AML and ALL specimens. Our findings suggest that dyslocalization of HDAC1 is a common feature in AML. Importantly, HDAC1 modifications possess prognostic power for patient survival. Our findings suggest that altered HDAC1 localization is an explanation for the observed benefit of HDAC inhibitors in AML therapy. [Copyright &y& Elsevier]

The article discusses a study which described a web-based application for risk assessment of chemotherapy in older patients with acute myeloid leukaemia. Multiple regression analysis was employed in this study develop risk scores with or without cytogenetic and molecular risk data. Results of the study showed that body temperature, hemoglobin and fibrinogen were some of the factors significantly associated with complete remission (CR) or early death (ED) in these patients. Particular focus is given to the probability of CR with cytogenetic data.

Abstract: VEGFR and c-Kit signaling pathways may contribute to the pathophysiology of acute myeloid leukemia (AML). Thirty-five patients with AML received cediranib (RECENTIN™), an oral, highly potent VEGF signaling inhibitor with c-Kit activity, at doses of ≤30mg/day. The most common adverse events were diarrhea, hypertension and fatigue. Six patients experienced an objective response (3 each at 20 and 30mg). Dose- and time-dependent reductions in sVEGFR-2 were observed, and there was a positive correlation between cediranib exposure and the change in plasma VEGF levels from baseline. Cediranib was generally well tolerated and showed preliminary evidence of activity as a monotherapy. [Copyright &y& Elsevier]

Abstract: The description of the molecular pathogenesis of acute myeloid leukemias (AML) has seen dramatic progress over the last years. Two major types of genetic events have been described that are crucial for leukemic transformation: alterations in myeloid transcription factors governing hematopoietic differentiation and activating mutations of signal transduction intermediates. These processes are highly interdependent, since the molecular events changing the transcriptional control in hematopoietic progenitor cells modify the composition of signal transduction molecules available for growth factor receptors, while the activating mutations in signal transduction molecules induce alterations in the activity and expression of several transcription factors that are crucial for normal myeloid differentiation. The purpose of this article is to review the current literature describing these genetic events, their biological consequences and their clinical implications. As the article will show, the recent description of several critical transforming mutations in AML may soon give rise to more efficient and less toxic molecularly targeted therapies of this deadly disease. [Copyright &y& Elsevier]