Risk stratification of intermediate-risk acute myeloid leukemia: integrative analysis of a multitude of gene mutation and gene expression markers

Prognostic impact of CEBPA mutational subgroups in adult AML

Despite recent refinements in the diagnostic and prognostic assessment of CEBPA mutations in AML, several questions remain open, i.e. implications of different types of basic region leucin zipper (bZIP) mutations, the role of co-mutations and the allelic state. Using pooled primary data analysis on 1010 CEBPA-mutant adult AML patients, a comparison was performed taking into account the type of mutation (bZIP: either typical in-frame insertion/deletion (InDel) mutations (bZIPInDel), frameshift InDel or nonsense mutations inducing translational stop (bZIPSTOP) or single base-pair missense alterations (bZIPms), and transcription activation domain (TAD) mutations) and the allelic state (single (smCEBPA) vs. double mutant (dmCEBPA)). Only bZIPInDel patients had significantly higher rates of complete remission and longer relapse free and overall survival (OS) compared with all other CEBPA-mutant subgroups. Moreover, co-mutations in bZIPInDel patients (e.g. GATA2, FLT3, WT1 as well as ELN2022 adverse risk aberrations) had no independent impact on OS, whereas in non-bZIPInDel patients, grouping according to ELN2022 recommendations added significant prognostic information. In conclusion, these results demonstrate bZIPInDel mutations to be the major independent determinant of outcome in CEBPA-mutant AML, thereby refining current classifications according to WHO (including all dmCEBPA and smCEBPA bZIP) as well as ELN2022 and ICC recommendations (including CEBPA bZIPms).

The diagnostic/prognostic roles and biological function of the IFIT family members in acute myeloid leukemia

BACKGROUND

The Interferon-induced protein with tetratricopeptide repeat (IFIT) family, IFIT1/2/3/5, play an important role in different tumors progression. However, the prognosis significance and biological role of IFIT family members in acute myeloid leukemia (AML) remains unclear.

METHODS

We obtained the gene expression data and clinical information of 173 AML patients from The Cancer Genome Atlas (TCGA) database. Several databases were used in our study, including GEPIA, MethSurv, STRING, GSCA and GeneMANIA database.

RESULTS

The mRNA expression of IFIT1/2/3/5 was elevated in AML patients and had a high ability to distinguish AML from controls based on the receiver operating characteristic (ROC) curve (AUC > 0.9). Kaplan-Meier survival analysis showed that higher levels of IFIT2/3/5 expression predict poor prognosis in AML patients. Besides, the DNA methylation analysis suggested that 7 CpG sites of IFIT2, 4 CpG sites of IFIT3 and 10 CpG sites of IFIT5 were significantly associated with the prognosis of AML patients. In addition, IFIT2/3/5 expression was significantly positively associated with the immune cell infiltration and immune checkpoint expression, such as CTLA4, PDCD1, LAG3, and TIGIT. Finally, drug sensitivity analysis revealed that AML patients with high expression of IFIT2/3/5 were resistant to multiple drugs, but sensitive to dasatinib.

CONCLUSION

IFIT family genes might serve as biomarkers for diagnosis, prognosis and drug sensitivity in AML patients. The activation or blocking of IFIT-related signaling pathways may provide novel insights into immunotherapy for patients with AML.

Verification of prognostic expression biomarkers is improved by examining enriched leukemic blasts rather than mononuclear cells from acute myeloid leukemia patients

BACKGROUND

Studies have not systematically compared the ability to verify performance of prognostic transcripts in paired bulk mononuclear cells versus viable CD34-expressing leukemic blasts from patients with acute myeloid leukemia. We hypothesized that examining the homogenous leukemic blasts will yield different biological information and may improve prognostic performance of expression biomarkers.

METHODS

To assess the impact of cellular heterogeneity on expression biomarkers in acute myeloid leukemia, we systematically examined paired mononuclear cells and viable CD34-expressing leukemic blasts from SWOG diagnostic specimens. After enrichment, patients were assigned into discovery and validation cohorts based on availability of extracted RNA. Analyses of RNA sequencing data examined how enrichment impacted differentially expressed genes associated with pre-analytic variables, patient characteristics, and clinical outcomes.

RESULTS

Blast enrichment yielded significantly different expression profiles and biological pathways associated with clinical characteristics (e.g., cytogenetics). Although numerous differentially expressed genes were associated with clinical outcomes, most lost their prognostic significance in the mononuclear cells and blasts after adjusting for age and ELN risk, with only 11 genes remaining significant for overall survival in both cell populations (CEP70, COMMD7, DNMT3B, ECE1, LNX2, NEGR1, PIK3C2B, SEMA4D, SMAD2, TAF8, ZNF444). To examine the impact of enrichment on biomarker verification, these 11 candidate biomarkers were examined by quantitative RT/PCR in the validation cohort. After adjusting for ELN risk and age, expression of 4 genes (CEP70, DNMT3B, ECE1, and PIK3CB) remained significantly associated with overall survival in the blasts, while none met statistical significance in mononuclear cells.

CONCLUSIONS

This study provides insights into biological information gained/lost by examining viable CD34-expressing leukemic blasts versus mononuclear cells from the same patient and shows an improved verification rate for expression biomarkers in blasts.

The expression level of Neuronal Calcium Sensor 1 can predict the prognosis of cytogenetically normal AML

Acute myeloid leukemia (AML) is malignant clonal expansion of myeloid blasts with high heterogeneity and numerous molecular biomarkers have been found to judge the prognosis in some specific classifications of AML. Furthermore, as for patients with cytogenetically normal acute myeloid leukemia (CN-AML), we need to find more new biomarkers to predict the patients' outcomes. Recently, the expression level of Neuronal Calcium Sensor 1 (NCS1) has been associated with the prognosis of breast cancer and hepatocellular carcinoma, but nothing related has been reported about hematological malignancies. Therefore, we make this study to explore the relationship between the NCS1 expression level and CN-AML. We analyzed the relation between survival and NCS1 RNA expression through 75 CN-AML patients from Cancer Genome Atlas (TCGA) database and 433 CN-AML patients (3 independent datasets) from Gene Expression Omnibus (GEO) database. Additionally, we compared the NCS1 RNA expression between 138 leukemia stem cells positive (LSCs+) samples and 89 leukemia stem cells negative (LSCs-) samples from 78 AML patients from GSE76004 dataset. In our study, CN-AML patients with high expression level of NCS1 have longer EFS or OS. In addition, the NCS1 expression level in leukemia stem cells was low (p = 0.00039). According to these findings, we concluded that the high expression of NCS1 can predict favorable prognosis in CN-AML patients. Furthermore, our work put forward that NCS1 expresses lower in LSCs+, which might be an important mechanism to explain the aggressiveness of AML.

EVI1 drives leukemogenesis through aberrant ERG activation

Chromosomal rearrangements involving the MDS1 and EVI1 complex locus (MECOM) on chromosome 3q26 define an aggressive subtype of acute myeloid leukemia (AML) that is associated with chemotherapy resistance and dismal prognosis. Established treatment regimens commonly fail in these patients, therefore, there is an urgent need for new therapeutic concepts that will require a better understanding of the molecular and cellular functions of the ecotropic viral integration site 1 (EVI1) oncogene. To characterize gene regulatory functions of EVI1 and associated dependencies in AML, we developed experimentally tractable human and murine disease models, investigated the transcriptional consequences of EVI1 withdrawal in vitro and in vivo, and performed the first genome-wide CRISPR screens in EVI1-dependent AML. By integrating conserved transcriptional targets with genetic dependency data, we identified and characterized the ETS transcription factor ERG as a direct transcriptional target of EVI1 that is aberrantly expressed and selectively required in both human and murine EVI1-driven AML. EVI1 controls the expression of ERG and occupies a conserved intragenic enhancer region in AML cell lines and samples from patients with primary AML. Suppression of ERG induces terminal differentiation of EVI1-driven AML cells, whereas ectopic expression of ERG abrogates their dependence on EVI1, indicating that the major oncogenic functions of EVI1 are mediated through aberrant transcriptional activation of ERG. Interfering with this regulatory axis may provide entry points for the development of rational targeted therapies.

Clinical features and prognostic implications of ecotropic viral integration site 1 (EVI1) in childhood acute lymphoblastic leukemia

In contrast to the extensive knowledge on EVI1 in myeloid malignancies, few data are available on the EVI1 transcript in pediatric ALL. The purpose of this study was to examine the clinical and biological significance of EVI1 and validate its prognostic significance in pediatric patients with ALL. Here, we examined the clinical and biological significance of EVI1 expression, as measured by real-time polymerase chain reaction (PCR) in 837 children with newly diagnosed ALL treated on the National Protocol of Childhood Leukemia in China (NPCLC)-ALL-2008 protocol, and aimed to explore their prognostic significance in pediatric ALL patients. The EVI1 expression was detected in 27 of 837 (3.2%) patients. No statistically significant differences in prednisone response, complete remission (CR) rates and relapse rates were found between EVI1 overexpression (EVI1⁺) group and EVI1^- group. Moreover, we found no significant difference in event-free survival (EFS) and overall survival (OS) between these two groups, also multivariate analysis did not identify EVI1⁺ as an independent prognostic factor. In the subgroup analysis, there was no difference in clinical outcome between EVI1⁺ and EVI1^- patients in standard‑risk (SR), intermediate-risk (IR) and high-risk (HR) groups. In the minimal residual disease (MRD)<10^-4 group, EVI1⁺ patients have significantly lower EFS and OS rates compared to EVI1^- patients. Further large‑scale and well‑designed prospective studies are required to confirm the results in the future.

A validation study of potential prognostic DNA methylation biomarkers in patients with acute myeloid leukemia using a custom DNA methylation sequencing panel

BACKGROUND

Multiple studies have reported the prognostic impact of DNA methylation changes in acute myeloid leukemia (AML). However, these epigenetic markers have not been thoroughly validated and therefore are still not considered in clinical practice. Hence, we aimed to independently verify results of selected studies describing the relationship between DNA methylation of specific genes and their prognostic potential in predicting overall survival (OS) and event-free survival (EFS).

RESULTS

Fourteen studies (published 2011-2019) comprising of 27 genes were subjected to validation by a custom NGS-based sequencing panel in 178 newly diagnosed non-M3 AML patients treated by 3 + 7 induction regimen. The results were considered as successfully validated, if both the log-rank test and multivariate Cox regression analysis had a p-value ≤ 0.05. The predictive role of DNA methylation was confirmed for three studies comprising of four genes: CEBPA (OS: p = 0.02; EFS: p = 0.03), PBX3 (EFS: p = 0.01), LZTS2 (OS: p = 0.05; EFS: p = 0.0003), and NR6A1 (OS: p = 0.004; EFS: p = 0.0003). For all of these genes, higher methylation was an indicator of longer survival. Concurrent higher methylation of both LZTS2 and NR6A1 was highly significant for survival in cytogenetically normal (CN) AML group (OS: p < 0.0001; EFS: p < 0.0001) as well as for the whole AML cohort (OS: p = 0.01; EFS < 0.0001). In contrast, for two studies reporting the poor prognostic effect of higher GPX3 and DLX4 methylation, we found the exact opposite, again linking higher GPX3 (OS: p = 0.006; EFS: p < 0.0001) and DLX4 (OS: p = 0.03; EFS = 0.03) methylation to a favorable treatment outcome. Individual gene significance levels refer to the outcomes of multivariate Cox regression analysis.

CONCLUSIONS

Out of twenty-seven genes subjected to DNA methylation validation, a prognostic role was observed for six genes. Therefore, independent validation studies are necessary to reveal truly prognostic DNA methylation changes and to enable the introduction of these promising epigenetic markers into clinical practice.

Establishment of Prognosis Model in Acute Myeloid Leukemia Based on Hypoxia Microenvironment, and Exploration of Hypoxia-Related Mechanisms

Acute myeloid leukemia (AML) is a highly heterogeneous hematologic neoplasm with poor survival outcomes. However, the routine clinical features are not sufficient to accurately predict the prognosis of AML. The expression of hypoxia-related genes was associated with survival outcomes of a variety of hematologic and lymphoid neoplasms. We established an 18-gene signature-based hypoxia-related prognosis model (HPM) and a complex model that consisted of the HPM and clinical risk factors using machine learning methods. Both two models were able to effectively predict the survival of AML patients, which might contribute to improving risk classification. Differentially expressed genes analysis, Gene Ontology (GO) categories, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed to reveal the underlying functions and pathways implicated in AML development. To explore hypoxia-related changes in the bone marrow immune microenvironment, we used CIBERSORT to calculate and compare the proportion of 22 immune cells between the two groups with high and low hypoxia-risk scores. Enrichment analysis and immune cell composition analysis indicated that the biological processes and molecular functions of drug metabolism, angiogenesis, and immune cell infiltration of bone marrow play a role in the occurrence and development of AML, which might help us to evaluate several hypoxia-related metabolic and immune targets for AML therapy.

FLT3 inhibition by olverembatinib (HQP1351) downregulates MCL-1 and synergizes with BCL-2 inhibitor lisaftoclax (APG-2575) in preclinical models of FLT3-ITD mutant acute myeloid leukemia

Introduction

FLT3-ITD mutations occur in approximately 25% of patients with acute myeloid leukemia (AML) and are associated with poor prognosis. Despite initial efficacy, short duration of response and high relapse rates limit clinical use of selective FLT3 inhibitors. Combination approaches with other targeted therapies may achieve better clinical outcomes.

Materials and methods

Anti-leukemic activity of multikinase inhibitor olverembatinib (HQP1351), alone or in combination with BCL-2 inhibitor lisaftoclax (APG-2575), was evaluated in FLT3-ITD mutant AML cell lines in vitro and in vivo. A patient-derived FLT3-ITD mutant AML xenograft model was also used to assess the anti-leukemic activity of this combination.

Results

HQP1351 potently induced apoptosis and inhibited FLT3 signaling in FLT3-ITD mutant AML cell lines MV-4-11 and MOLM-13. HQP1351 monotherapy also significantly suppressed growth of FLT3-ITD mutant AML xenograft tumors and prolonged survival of tumor-bearing mice. HQP1351 and APG-2575 synergistically induced apoptosis in FLT3-ITD mutant AML cells and suppressed growth of MV-4–11 xenograft tumors. Combination therapy improved survival of tumor bearing-mice in a systemic MOLM-13 model and showed synergistic anti-leukemic effects in a patient-derived FLT3-ITD mutant AML xenograft model. Mechanistically, HQP1351 downregulated expression of myeloid-cell leukemia 1 (MCL-1) by suppressing FLT3-STAT5 (signal transducer and activator of transcription 5) signaling and thus enhanced APG-2575-induced apoptosis in FLT3-ITD mutant AML cells.

Conclusions

FLT3 inhibition by HQP1351 downregulates MCL-1 and synergizes with BCL-2 inhibitor APG-2575 to potentiate cellular apoptosis in FLT3-ITD mutant AML. Our findings provide a scientific rationale for further clinical investigation of HQP1351 combined with APG-2575 in patients with FLT3-ITD mutant AML.

IDH2 mutations in patients with normal karyotype AML predict favorable responses to daunorubicin, cytarabine and cladribine regimen

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) genes occur in about 20% patients with acute myeloid leukemia (AML), leading to DNA hypermethylation and epigenetic deregulation. We assessed the prognostic significance of IDH1/2 mutations (IDH1/2⁺) in 398 AML patients with normal karyotype (NK-AML), treated with daunorubicine + cytarabine (DA), DA + cladribine (DAC), or DA + fludarabine. IDH2 mutation was an independent favorable prognostic factor for 4-year overall survival (OS) in total NK-AML population (p = 0.03, censoring at allotransplant). We next evaluated the effect of addition of cladribine to induction regimen on the patients’ outcome according to IDH1/2 mutation status. In DAC group, 4-year OS was increased in IDH2⁺ patients, compared to IDH-wild type group (54% vs 33%; p = 0.0087, censoring at allotransplant), while no difference was observed for DA-treated subjects. In multivariate analysis, DAC independently improved the survival of IDH2⁺ patients (HR = 0.6 [0.37–0.93]; p = 0.024; censored at transplant), indicating that this group specifically benefits from cladribine-containing therapy. In AML cells with R140Q or R172K IDH2 mutations, cladribine restrained mutations-related DNA hypermethylation. Altogether, DAC regimen produces better outcomes in IDH2⁺ NK-AML patients than DA, and this likely results from the hypomethylating activity of cladribine. Our observations warrant further investigations of induction protocols combining cladribine with IDH1/2 inhibitors in IDH2-mutant.

A Novel Role for Brain and Acute Leukemia Cytoplasmic (BAALC) in Human Breast Cancer Metastasis

Brain and Acute Leukemia, Cytoplasmic (BAALC) is a protein that controls leukemia cell proliferation, differentiation, and survival and is overexpressed in several cancer types. The gene is located in the chromosomal region 8q22.3, an area commonly amplified in breast cancer and associated with poor prognosis. However, the expression and potential role of BAALC in breast cancer has not widely been examined. This study investigates BAALC expression in human breast cancers with the aim of determining if it plays a role in the pathogenesis of the disease. BAALC protein expression was examined by immunohistochemistry in breast cancer, and matched lymph node and normal breast tissue samples. The effect of gene expression on overall survival (OS), disease-free and distant metastasis free survival (DMFS) was assessed in silico using the Kaplan-Meier Plotter (n=3,935), the TCGA invasive breast carcinoma (n=960) and GOBO (n=821) data sets. Functional effects of BAALC expression on breast cancer proliferation, migration and invasion were determined in vitro. We demonstrate herein that BAALC expression is progressively increased in primary and breast cancer metastases when compared to normal breast tissue. Increased BAALC mRNA is associated with a reduction in DMFS and disease-free survival, but not OS, in breast cancer patients, even when corrected for tumor grade. We show that overexpression of BAALC in MCF-7 breast cancer cells increases the proliferation, anchorage-independent growth, invasion, and migration capacity of these cells. Conversely, siRNA knockdown of BAALC expression in Hs578T breast cancer cells decreases proliferation, invasion and migration. We identify that this BAALC associated migration and invasion is mediated by focal adhesion kinase (FAK)-dependent signaling and is accompanied by an increase in matrix metalloproteinase (MMP)-9 but not MMP-2 activity in vitro. Our data demonstrate a novel function for BAALC in the control of breast cancer metastasis, offering a potential target for the generation of anti-cancer drugs to prevent breast cancer metastasis.

Prognostic significance of combined BAALC and MN1 gene expression level in acute myeloid leukemia with normal karyotype

INTRODUCTION

Acute myeloid leukemia with normal karyotype (AML-NK) is the largest group of AML patients with very heterogeneous disease outcome. In order to ensure more precise risk stratification new molecular markers have been introduced, like expression level for BAALC (Brain and Acute Leukemia, Cytoplasmic) and MN1 (Meningioma 1) genes.

METHODS

In this study, we investigated expression level of both genes in 111 adult AML-NK at diagnosis and examined their prognostic potential.

RESULTS

BAALC and MN1 expression were detected in about one third of the patients, and positive correlation between these two genes was found. The BAALC⁺ /or MN1⁺ status was not associated with the presence of FLT3-ITD mutations, but exhibited strong correlation with NPM1^wt status (P < .001). Therefore, among BAALC⁺ /or MN1⁺ patients the most frequent ones were FLT3-ITD^- /NPM1^- double negative patients with intermediate prognosis. When BAALC⁺ /or MN1⁺ patients were divided into BAALC^high /BAALC^low (21/21) and MN1^high /MN1^low (21/22) groups, we detected that BAALC^high /or MN1^high patients had a tendency toward lower complete remission rate. Also, survival analysis showed that BAALC^high /or MN1^high patients had shorter disease-free survival and overall survival (OS). The most pronounced influence on prognosis was detected in FLT3-ITD^- /NPM1^- group of patients that are lacking reliable prognostic markers, where OS in BAALC^high /or MN1^high was only 5 months vs 25 months in BAALC^low /or MN1^low .

CONCLUSION

These findings indicate that BAALC and MN1 expression level could be used for more precise risk stratification of AML-NK patients and especially FLT3-ITD^- /NPM1^- patients, transforming this intermediate-risk group, into a group with an adverse prognosis.

Development and validation of a prognostic model for adult patients with acute myeloid leukaemia

Background

The high heterogeneity of acute myeloid leukaemia (AML) reflected in the patient- and disease-related factors accounts for the unsatisfactory prognosis despite the introduction of novel therapeutic approaches and drugs in recent years.

Methods

In the development set (n = 412), parameters including age, hematopoietic cell transplantation-comorbidity index, white blood cell count, hemoglobin, biallelic CEBPA mutations, DNMT3A mutations, FLT3-ITD/NPM1 status, and ELN cytogenetic risk status were identified as independent prognostic factors for overall survival (OS) in the multivariable Cox regression analysis. A nomogram combining these predictors for individual risk estimation was established thereby.

Findings

The prognostic model demonstrated promising performance in the development cohort. The calibration plot, C-index (0.74), along with the 1-, 2- and 3-year area under the receiver operating characteristic curve (AUC, 0.76, 0.79, and 0.74, respectively) in the validation set (n = 238) substantiated the robustness of the model. In addition to stratifying young (age ≤ 60 years) and elderly patients (age > 60 years) into three and two risk groups with significant distinct outcomes, the prognostic model succeeded in distinguishing eligible candidates for hematopoietic stem cell transplantation.

Interpretation

The prognostic model is capable of survival prediction, risk stratification and helping with therapeutic decision-making with the use of easily acquired variables in daily clinical routine.

Funding

This work was supported in part by grants from the National Natural Science Foundation of China (81770141), the National Key R&D Program of China (2016YFE0202800), and Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support (20161406).

High PRDM16 expression predicts poor outcomes in adult acute myeloid leukemia patients with intermediate cytogenetic risk: a comprehensive cohort study from a single Chinese center

Acute myeloid leukemia with intermediate cytogenetic risk (ICR-AML) needs to be stratified and abnormal gene expression might be prognostic. PR/SET domain 16 (PRDM16) transcript levels were assessed in 267 consecutive adult ICR-AML patients at diagnosis by real-time quantitative PCR. 38.2% patients had PRDM16 transcript levels higher than the upper limit of normal bone marrow samples. Through ROC curve analysis and comparison of relapse-free survival (RFS), the optimal cutoff value of PRDM16 transcript levels was identified to group patients into high expression (PRDM16-H, 21.3%) and low expression (PRDM16-L). PRDM16-H was significantly associated with lower 4-year RFS and overall survival (OS) rates in the entire cohort, patients with normal karyotypes, FLT3-ITD (-) and NPM1 mutation (+)/FLT3-ITD (-) patients (all p < .05). Multivariate analysis showed that PRDM16-H was an independent adverse prognostic factor for RFS and OS in the entire cohort. Therefore, high PRDM16 expression at diagnosis predicts poor outcomes in adult ICR-AML patients.

AML risk stratification models utilizing ELN-2017 guidelines and additional prognostic factors: a SWOG report

Background

The recently updated European LeukemiaNet risk stratification guidelines combine cytogenetic abnormalities and genetic mutations to provide the means to triage patients with acute myeloid leukemia for optimal therapies. Despite the identification of many prognostic factors, relatively few have made their way into clinical practice.

Methods

In order to assess and improve the performance of the European LeukemiaNet guidelines, we developed novel prognostic models using the biomarkers from the guidelines, age, performance status and select transcript biomarkers. The models were developed separately for mononuclear cells and viable leukemic blasts from previously untreated acute myeloid leukemia patients (discovery cohort, N = 185) who received intensive chemotherapy. Models were validated in an independent set of similarly treated patients (validation cohort, N = 166).

Results

Models using European LeukemiaNet guidelines were significantly associated with clinical outcomes and, therefore, utilized as a baseline for comparisons. Models incorporating age and expression of select transcripts with biomarkers from European LeukemiaNet guidelines demonstrated higher area under the curve and C-statistics but did not show a substantial improvement in performance in the validation cohort. Subset analyses demonstrated that models using only the European LeukemiaNet guidelines were a better fit for younger patients (age < 55) than for older patients. Models integrating age and European LeukemiaNet guidelines visually showed more separation between risk groups in older patients. Models excluding results for ASXL1, CEBPA, RUNX1 and TP53, demonstrated that these mutations provide a limited overall contribution to risk stratification across the entire population, given the low frequency of mutations and confounding risk factors.

Conclusions

While European LeukemiaNet guidelines remain a critical tool for triaging patients with acute myeloid leukemia, the findings illustrate the need for additional prognostic factors, including age, to improve risk stratification.

HMGA Proteins in Hematological Malignancies

The high mobility group AT-Hook (HMGA) proteins are a family of nonhistone chromatin remodeling proteins known as "architectural transcriptional factors". By binding the minor groove of AT-rich DNA sequences, they interact with the transcription apparatus, altering the chromatin modeling and regulating gene expression by either enhancing or suppressing the binding of the more usual transcriptional activators and repressors, although they do not themselves have any transcriptional activity. Their involvement in both benign and malignant neoplasias is well-known and supported by a large volume of studies. In this review, we focus on the role of the HMGA proteins in hematological malignancies, exploring the mechanisms through which they enhance neoplastic transformation and how this knowledge could be exploited to devise tailored therapeutic strategies.

DNA methylation markers in the diagnosis and prognosis of common leukemias

The ability to identify a specific type of leukemia using minimally invasive biopsies holds great promise to improve the diagnosis, treatment selection, and prognosis prediction of patients. Using genome-wide methylation profiling and machine learning methods, we investigated the utility of CpG methylation status to differentiate blood from patients with acute lymphocytic leukemia (ALL) or acute myelogenous leukemia (AML) from normal blood. We established a CpG methylation panel that can distinguish ALL and AML blood from normal blood as well as ALL blood from AML blood with high sensitivity and specificity. We then developed a methylation-based survival classifier with 23 CpGs for ALL and 20 CpGs for AML that could successfully divide patients into high-risk and low-risk groups, with significant differences in clinical outcome in each leukemia type. Together, these findings demonstrate that methylation profiles can be highly sensitive and specific in the accurate diagnosis of ALL and AML, with implications for the prediction of prognosis and treatment selection.

Cost-Effectiveness Analysis of a HMGA2 Prognostic Test for Acute Myeloid Leukemia in a Canadian Setting

BACKGROUND

Current strategies for risk stratification of patients with acute myeloid leukemia assign approximately 40% of patients to the intermediate-risk group, where uncertainty about optimal therapy still persists.

OBJECTIVE

The objective of this study was to assess the cost effectiveness of a HMGA2 prognostic test based on HMGA2+/HMGA2- expression, which improves genetic risk stratification in acute myeloid leukemia, and compare this test with the current standard of care in Canada.

METHODS

A cost-effectiveness model was developed from the Canadian National Healthcare Service and societal perspective using data from the Quebec Leukemia Cell Bank, published literature, and physician surveys. The model includes a lifetime horizon assessing the HMGA2 test vs. standard of care.

RESULTS

The HMGA2 test outperformed the standard of care at all time horizons culminating with estimated improvements of 1.92 and 3.12 months in leukemia-free survival and overall survival, respectively. Costs associated with the HMGA2 test were consistently lower, except diagnostic costs, routine medical costs, and costs related to infections and false positives. From a societal perspective, total lifetime costs were $161,358 CAD and $151,908 CAD with the standard of care and the HMGA2 test, respectively. The incremental quality-adjusted life-year gain was 0.138, which led to dominance over the standard of care. Deterministic sensitivity analyses confirmed the results of the base-case scenario. Probabilistic sensitivity analyses revealed that for a willingness-to-pay threshold of $100,000 CAD, the probability of cost effectiveness was 87.19%.

CONCLUSIONS

The HMGA2 test is estimated to improve leukemia-free survival and overall survival outcomes, and yield costs savings from a healthcare system and societal perspective.

Acute Leukemia: Diagnosis and Treatment

OBJECTIVE

To provide an overview of acute leukemia, comparing incidence, presenting symptoms, diagnosis, prognosis, and treatment of the major subtypes.

DATA SOURCES

Review of articles dated 2010 to present in PubMed and CINAHL, and National Comprehensive Cancer Network Guidelines.

CONCLUSION

The diagnosis of acute leukemia is comprised of a variety of hematopoietic neoplasms that are both complex and unique. Each subtype of acute leukemia has defining characteristics that affect prognosis and treatment.

IMPLICATIONS FOR NURSING PRACTICE

Nurses play an integral role in the care of the patient with acute leukemia during and beyond hospitalization. Therefore, baseline knowledge of these diseases is essential. Early symptom recognition is central in the management of oncologic emergencies.

Expression Pattern and Prognostic Significance of EVI1 Gene in Adult Acute Myeloid Leukemia Patients with Normal Karyotype

According to current criteria, patients with acute myeloid leukemia with normal karyotype (AML-NK) are classified as intermediate risk patients. There is a constant need for additional molecular markers that will help in substratification into more precise prognostic groups. One of the potential new markers is Ecotropic viral integration 1 site (EVI1) transcriptional factor, whose expression is dissregulated in abnormal hematopoietic process. The purpose of this study was to examine EVI1 gene expression in 104 adult AML-NK patients and on 10 healthy bone marrow donors using real-time polymerase chain reaction method, and to evaluate association between EVI1 expression level and other molecular and clinical features, and to examine its potential influence on the prognosis of the disease. Overexpression of EVI1 gene (EVI1 ⁺ status) was present in 17% of patients. Increased EVI1 expression was predominantly found in patients with lower WBC count (P = 0.003) and lower bone marrow blast percentage (P = 0.005). EVI1 ⁺ patients had lower WT1 expression level (P = 0.041), and were negative for FLT3-ITD and NPM1 mutations (P = 0.036 and P = 0.003). Patients with EVI1 ⁺ status had higher complete remission rate (P = 0.047), but EVI1 expression didn't influence overall and disease free survival. EVI1 expression status alone, cannot be used as a new marker for more precise substratification of AML-NK patients. Further investigations conducted on larger number of patients may indicate how EVI1 expression could influence the prognosis and outcome of AML-NK patients, by itself, or in the context of other molecular and clinical parameters.

High IL2RA mRNA expression is an independent adverse prognostic biomarker in core binding factor and intermediate-risk acute myeloid leukemia

BACKGROUND

Elevated protein expressions of CD markers such as IL2RA/CD25, CXCR4/CD184, CD34 and CD56 are associated with adverse prognosis in acute myeloid leukemia (AML). However, the prognostic value of mRNA expressions of these CD markers in AML remains unclear. Through our pilot evaluation, IL2RA mRNA expression appeared to be the best candidate as a prognostic biomarker. Therefore, the aim of this study is to characterize the prognostic value of IL2RA mRNA expression and evaluate its potential to refine prognostification in AML.

METHODS

In a cohort of 239 newly diagnosed AML patients, IL2RA mRNA expression were measured by TaqMan realtime quantitative PCR. Morphological, cytogenetics and mutational analyses were also performed. In an intermediate-risk AML cohort with 66 patients, the mRNA expression of prognostic biomarkers (BAALC, CDKN1B, ERG, MECOM/EVI1, FLT3, ID1, IL2RA, MN1 and WT1) were quantified by NanoString technology. A TCGA cohort was analyzed to validate the prognostic value of IL2RA. For statistical analysis, Mann-Whitney U test, Fisher exact test, logistic regression, Kaplan-Meier and Cox regression analyses were used.

RESULTS

In AML cohort of 239 patients, high IL2RA mRNA expression independently predicted shorter relapse free survival (RFS, p < 0.001) and overall survival (OS, p < 0.001) irrespective of age, cytogenetics, FLT3-ITD or c-KIT D816V mutational status. In core binding factor (CBF) AML, high IL2RA mRNA expression correlated with FLT3-ITD status (p = 0.023). Multivariable analyses revealed that high IL2RA expression (p = 0.002), along with c-KIT D816V status (p = 0.013) significantly predicted shorter RFS, whereas only high IL2RA mRNA expression (p = 0.014) significantly predicted shorter OS in CBF AML. In intermediate-risk AML in which multiple gene expression markers were tested by NanoString, IL2RA significantly correlated with ID1 (p = 0.006), FLT3 (p = 0.007), CDKN1B (p = 0.033) and ERG (p = 0.030) expressions. IL2RA (p < 0.001) and FLT3 (p = 0.008) expressions remained significant in predicting shorter RFS, whereas ERG (p = 0.008) and IL2RA (p = 0.044) remained significant in predicting shorter OS. Similar analyses in TCGA intermediate-risk AML showed the independent prognostic role of IL2RA in predicting event free survival (p < 0.001) and OS (p < 0.001).

CONCLUSIONS

High IL2RA mRNA expression is an independent and adverse prognostic factor in AML and specifically stratifies patients to worse prognosis in both CBF and intermediate-risk AML.

Incubation of Immune Cell Grafts With MAX.16H5 IgG1 Anti-Human CD4 Antibody Prolonged Survival After Hematopoietic Stem Cell Transplantation in a Mouse Model for Fms Like Tyrosine Kinase 3 Positive Acute Myeloid Leukemia

Despite the constant development of innovative therapeutic options for hematological malignancies, the gold-standard therapy regimen for curative treatment often includes allogeneic hematopoietic stem cell transplantation (HSCT). The graft-vs.-leukemia effect (GVL) is one of the main therapeutic goals that arises from HSCT. On the other hand, graft-vs.-host disease (GVHD) is still one of the main and most serious complications following allogeneic HSCT. In acute myeloid leukemia (AML), HSCT together with high-dose chemotherapy is used as a treatment option. An aggressive progression of the disease, a decreased response to treatment, and a poor prognosis are connected to internal tandem duplication (ITD) mutations in the Fms like tyrosine kinase 3 (FLT3) gene, which affects around 30% of AML patients. In this study, C3H/HeN mice received an allogeneic graft together with 32D-FLT3^ITD AML cells to induce acute GVHD and GVL. It was examined if pre-incubation of the graft with the anti-human cluster of differentiation (CD) 4 antibody MAX.16H5 IgG₁ prevented the development of GVHD and whether the graft function was impaired. Animals receiving grafts pre-incubated with the antibody together with FLT3^ITD AML cells survived significantly longer than mice receiving untreated grafts. The observed prolonged survival due to MAX.16H5 incubation of immune cell grafts prior to transplantation may allow an extended application of additional targeted strategies in the treatment of AML.

A distinct immunophenotype identifies a subset of NPM1-mutated AML with TET2 or IDH1/2 mutations and improved outcome

Recent work has identified distinct molecular subgroups of acute myeloid leukemia (AML) with implications for disease classification and prognosis. NPM1 is one of the most common recurrently mutated genes in AML. NPM1 mutations often co-occur with FLT3-ITDs and mutations in genes regulating DNA methylation, such as DNMT3A, TET2, and IDH1/2. It remains unclear whether these genetic alterations are associated with distinct immunophenotypic findings or affect prognosis. We identified 133 cases of NPM1-mutated AML and correlated sequencing data with immunophenotypic and clinical findings. Of 84 cases (63%) that lacked monocytic differentiation ("myeloid AML"), 40 (48%) demonstrated an acute promyelocytic leukemia-like (APL-like) immunophenotype by flow cytometry, with absence of CD34 and HLA-DR and strong myeloperoxidase expression, in the absence of a PML-RARA translocation. Pathologic variants in TET2, IDH1, or IDH2 were identified in 39/40 APL-like cases. This subset of NPM1-mutated AML was associated with longer relapse-free and overall survival, when compared with cases that were positive for CD34 and/or HLA-DR. The combination of NPM1 and TET2 or IDH1/2 mutations along with an APL-like immunophenotype identifies a distinct subtype of AML. Further studies addressing its biology and clinical significance may be especially relevant in the era of IDH inhibitors and recent work showing efficacy of ATRA therapy in NPM1 and IDH1-mutated AML.

High expression of HMGA2 independently predicts poor clinical outcomes in acute myeloid leukemia

In acute myeloid leukemia (AML), risk stratification based on cytogenetics and mutation profiling is essential but remains insufficient to select the optimal therapy. Accurate biomarkers are needed to improve prognostic assessment. We analyzed RNA sequencing and survival data of 430 AML patients and identified HMGA2 as a novel prognostic marker. We validated a quantitative PCR test to study the association of HMGA2 expression with clinical outcomes in 358 AML samples. In this training cohort, HMGA2 was highly expressed in 22.3% of AML, mostly in patients with intermediate or adverse cytogenetics. High expression levels of HMGA2 (H + ) were associated with a lower frequency of complete remission (58.8% vs 83.4%, P < 0.001), worse 3-year overall survival (OS, 13.2% vs 43.5%, P < 0.001) and relapse-free survival (RFS, 10.8% vs 44.2%, P < 0.001). A positive HMGA2 test also identified a subgroup of patients unresponsive to standard treatments. Multivariable analyses showed that H + was independently associated with significantly worse OS and RFS, including in the intermediate cytogenetic risk category. These associations were confirmed in a validation cohort of 260 patient samples from the UK NCRI AML17 trial. The HMGA2 test could be implemented in clinical trials developing novel therapeutic strategies for high-risk AML.

High expression of HMGA2 independently predicts poor clinical outcomes in acute myeloid leukemia

In acute myeloid leukemia (AML), risk stratification based on cytogenetics and mutation profiling is essential but remains insufficient to select the optimal therapy. Accurate biomarkers are needed to improve prognostic assessment. We analyzed RNA sequencing and survival data of 430 AML patients and identified HMGA2 as a novel prognostic marker. We validated a quantitative PCR test to study the association of HMGA2 expression with clinical outcomes in 358 AML samples. In this training cohort, HMGA2 was highly expressed in 22.3% of AML, mostly in patients with intermediate or adverse cytogenetics. High expression levels of HMGA2 (H + ) were associated with a lower frequency of complete remission (58.8% vs 83.4%, P < 0.001), worse 3-year overall survival (OS, 13.2% vs 43.5%, P < 0.001) and relapse-free survival (RFS, 10.8% vs 44.2%, P < 0.001). A positive HMGA2 test also identified a subgroup of patients unresponsive to standard treatments. Multivariable analyses showed that H + was independently associated with significantly worse OS and RFS, including in the intermediate cytogenetic risk category. These associations were confirmed in a validation cohort of 260 patient samples from the UK NCRI AML17 trial. The HMGA2 test could be implemented in clinical trials developing novel therapeutic strategies for high-risk AML.

High EVI1 Expression Predicts Poor Outcomes in Adult Acute Myeloid Leukemia Patients with Intermediate Cytogenetic Risk Receiving Chemotherapy

BACKGROUND Acute myeloid leukemia with intermediate cytogenetic risk (ICR-AML) needs to be stratified. The abnormal gene expression might be prognostic, and its cutoff value for patient grouping is pivotal. MATERIAL AND METHODS Ecotropic viral integration site 1 (EVI1) transcripts were assessed in 191 adult ICR-AML patients at diagnosis who received chemotherapy only. MLL-PTD, WT1 transcript levels, FLT3-ITD, and NPM1 mutations were simultaneously evaluated, and 27 normal bone marrow samples were tested to define normal threshold. RESULTS The normal upper limit of EVI1 transcript levels was 8.0%. Receiver operating characteristic curve analysis showed that 1.0% (a 0.9-log reduction from the normal limit) was the EVI1 optimal cutoff value for significantly differentiating relapse (P=0.049). A total of 23 patients (12%) had EVI1 levels ≥1.0%. EVI1 ≥1.0% had no effect on CR achievement, whereas it was significantly associated with lower 2-year relapse-free survival (RFS), disease-free survival (DFS), and overall survival (OS) rates in the entire cohort (P=0.0003, 0.0017, and 0.0009, respectively), patients with normal karyotypes (P=0.0032, 0.0047, and 0.0007, respectively), and FLT3-ITD (-) patients (all P<0.0001). Multivariate analysis showed that EVI1 ≥1.0% was an independent adverse prognostic factor for RFS, DFS, and OS in the entire cohort. In addition, patients with EVI1 transcript levels between 1.0% and 8.0% had 2-year RFS rates similar to those with EVI1 ≥8.0%, and they both had significantly lower RFS rates than those with EVI1 <1.0% (P=0.0005 and 0.027). CONCLUSIONS High EVI1 expression predicts poor outcome in ICR-AML patients receiving chemotherapy. The optimal cutoff value for patient stratification is different from the normal limit.

Gene mutation patterns of Chinese acute myeloid leukemia patients by targeted next-generation sequencing and bioinformatic analysis

PURPOSES

The conventional risk stratification of acute myeloid leukemia (AML), based on cytogenetics, cannot meet the demand for accurate prognostic evaluations. In recent years, gene mutations are found to be potential markers for more accurate risk stratification, but reports on mutation screening of Chinese AML are limited. We aim to display the mutation patterns of Chinese AML patients, reveal the genotype-phenotype correlations and make a comparison with Caucasians patients.

METHODS

Genome DNA from 78 patients' bone marrow were extracted for targeted gene mutation panel by next-generation sequencing (NGS) technology. Statistics and bioinformatics were used to analyze the correlations between gene mutations and clinical features, as well as the comparison of our results with the Cancer Genome Atlas Research Network (TCGA) public AML dataset.

RESULTS

We found patients with mutations of FLT3 and TET2 had higher bone marrow blasts, peripheral blasts and white blood cell (WBC) count, mutations of SRSF2 were related with age, and mutations of FLT3-ITD, DNMT3A, IDH1, TET2 and SRSF2 were risk factors for overall survival. What's more, we discovered 15 novel mutations and difference of mutational incidence in 6 genes between Chinese and Caucasians AML. Bioinformatic analysis revealed some relationship between gene mutations and expressions as well as drug sensitivities.

CONCLUSIONS

We made an investigation on the mutation patterns of Chinese AML patients by NGS technique and revealed correlations between gene mutations and clinical features. Thus we recommend routine testing of suspected genes for better prognostic prediction and individualized treatment.

Residual disease detection using targeted parallel sequencing predicts relapse in cytogenetically normal acute myeloid leukemia

Despite achieving complete remission after intensive therapy, most patients with cytogenetically normal (CN) AML relapse due to the persistence of submicroscopic residual disease. In this pilot study, we hypothesized that detection of leukemia-specific mutations following consolidation treatment using a targeted parallel sequencing approach predicts relapse. We included 34 AML patients of whom diagnostic material and remission bone marrow slides after at least one cycle of consolidation were available. Isolated DNA was screened for mutations in 19 genes using an Ion Torrent sequencing platform. Furthermore, the variant allelic frequency of distinct mutations was validated by digital PCR and sequencing using a barcoding approach. Twenty-seven out of 34 patients could be analyzed for mutation clearance. We identified 68 somatic mutations at diagnosis (median, 3 mutations per patient; range 1-5) and 22 of these were still detected in 16 patients after consolidation therapy with a reliable sensitivity of 0.5% (median, 1 mutation; range 0-3). The most frequent noncleared mutations were found in DNMT3A. However, as persistence of these mutations has recently been shown to be without any impact on relapse risk, we performed survival and relapse risk analysis excluding DNMT3A mutations. Importantly, persistence of non-DNMT3A mutations was associated with a higher risk of AML relapse (7/8 pts versus 6/19 pts; P = .013) and with a shorter relapse-free survival (333 days vs. not reached; log-rank P = .0219). Detection of residual disease by routine targeted parallel sequencing proved feasible and effective as persistence of somatic mutations other than DNMT3A were prognostic for relapse in CN AML.

Impact of Specimen Heterogeneity on Biomarkers in Repository Samples from Patients with Acute Myeloid Leukemia: A SWOG Report

INTRODUCTION

Current prognostic models for acute myeloid leukemia (AML) are inconsistent at predicting clinical outcomes for individual patients. Variability in the quality of specimens utilized for biomarker discovery and validation may contribute to this prognostic inconsistency.

METHODS

We evaluated the impact of sample heterogeneity on prognostic biomarkers and methods to mitigate any adverse effects of this heterogeneity in 240 cryopreserved bone marrow and peripheral blood specimens from AML patients enrolled on SWOG (Southwest Oncology Group) trials.

RESULTS

Cryopreserved samples displayed a broad range in viability (37% with viabilities ≤60%) and nonleukemic cell contamination (13% with lymphocyte percentages >20%). Specimen viability was impacted by transport time, AML immunophenotype, and, potentially, patients' age. The viability and cellular heterogeneity in unsorted samples significantly altered biomarker results. Enriching for viable AML blasts improved the RNA quality from specimens with poor viability and refined results for both DNA and RNA biomarkers. For example, FLT3-ITD allelic ratio, which is currently utilized to risk-stratify AML patients, was on average 1.49-fold higher in the viable AML blasts than in the unsorted specimens.

CONCLUSION

To our knowledge, this is the first study to provide evidence that using cryopreserved specimens can introduce uncontrollable variables that may impact biomarker results and enrichment for viable AML blasts may mitigate this impact.

Midostaurin/PKC412 for the treatment of newly diagnosed FLT3 mutation-positive acute myeloid leukemia

INTRODUCTION

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with inadequate treatment options. Approximately one-third of cases have a FLT3-ITD or FLT3-TKD mutation which leads to constitutive tyrosine kinase activation which contributes to leukemogenesis. The FLT3-ITD mutation is associated with a particularly poor prognosis. Midostaurin is a multi-kinase inhibitor active against the FLT3 receptor. Midostaurin was approved by the US FDA in April 2017 for treatment of newly diagnosed FLT3-mutant AML in combination with chemotherapy. Areas covered: Standard treatment of FLT3-mutant AML and outcomes. Early clinical development of midostaurin including pharmacokinetics and metabolism. The development of midostaurin in FLT3-mutant AML is then outlined including review of the phase I, II, and III trials of midostaurin as a single agent and in combination with chemotherapy. Expert commentary: The approval of midostaurin represents the first new therapy for AML in several decades. It is also the first targeted therapy approved for AML. Future studies will focus on defining mechanisms of resistance to midostaurin as well as establishing the role of midostaurin in combination with hypomethylating agents and as maintenance therapy. Second generation, more potent and selective FLT3 inhibitors are also in development; these agents need to be compared to midostaurin.

MiSTIC, an integrated platform for the analysis of heterogeneity in large tumour transcriptome datasets

Genome-wide transcriptome profiling has enabled non-supervised classification of tumours, revealing different sub-groups characterized by specific gene expression features. However, the biological significance of these subtypes remains for the most part unclear. We describe herein an interactive platform, Minimum Spanning Trees Inferred Clustering (MiSTIC), that integrates the direct visualization and comparison of the gene correlation structure between datasets, the analysis of the molecular causes underlying co-variations in gene expression in cancer samples, and the clinical annotation of tumour sets defined by the combined expression of selected biomarkers. We have used MiSTIC to highlight the roles of specific transcription factors in breast cancer subtype specification, to compare the aspects of tumour heterogeneity targeted by different prognostic signatures, and to highlight biomarker interactions in AML. A version of MiSTIC preloaded with datasets described herein can be accessed through a public web server (http://mistic.iric.ca); in addition, the MiSTIC software package can be obtained (github.com/iric-soft/MiSTIC) for local use with personalized datasets.

Midostaurin: a novel therapeutic agent for patients with FLT3-mutated acute myeloid leukemia and systemic mastocytosis

The development of FLT3-targeted inhibitors represents an important paradigm shift in the management of patients with highly aggressive fms-like tyrosine kinase 3-mutated (FLT3-mut) acute myeloid leukemia (AML). Midostaurin is an orally administered type III tyrosine kinase inhibitor which in addition to FLT3 inhibits c-kit, platelet-derived growth factor receptors, src, and vascular endothelial growth factor receptor. Midostaurin is the first FLT3 inhibitor that has been shown to significantly improve survival in younger patients with FLT3-mut AML when given in combination with standard cytotoxic chemotherapy based on the recently completed RATIFY study. Its role for maintenance therapy after allogeneic transplantation and use in combination with hypomethylating agents for older patients with FLT3-mut has not yet been defined. Midostaurin also has recently been shown to have significant activity in systemic mastocytosis and related disorders due to its inhibitory effect on c-kit bearing a D816V mutation. Activation of downstream pathways in both of these myeloid malignancies likely plays an important role in the development of resistance, and strategies to inhibit these downstream targets may be synergistic. Incorporating patient factors and tumor characteristics, such as FLT3 mutant to wild-type allele ratios and resistance mutations, likely will be important in the optimization of midostaurin and other FLT3 inhibitors in the treatment of myeloid neoplasms.

Pediatric Acute Megakaryoblastic Leukemia: Multitasking Fusion Proteins and Oncogenic Cooperations

Pediatric leukemia presents specific clinical and genetic features from adult leukemia but the underpinning mechanisms of transformation are still unclear. Acute megakaryoblastic leukemia (AMKL) is the malignant accumulation of progenitors of the megakaryocyte lineage that normally produce blood platelets. AMKL is diagnosed de novo, in patients showing a poor prognosis, or in Down syndrome (DS) patients with a better prognosis. Recent data show that de novo AMKL is primarily associated with chromosomal alterations leading to the expression of fusions between transcriptional regulators. This review highlights the most recurrent genetic events found in de novo pediatric AMKL patients and, based on recent functional analyses, proposes a mechanism of leukemogenesis common to de novo and DS-AMKL.

ETO2-GLIS2 Hijacks Transcriptional Complexes to Drive Cellular Identity and Self-Renewal in Pediatric Acute Megakaryoblastic Leukemia

Chimeric transcription factors are a hallmark of human leukemia, but the molecular mechanisms by which they block differentiation and promote aberrant self-renewal remain unclear. Here, we demonstrate that the ETO2-GLIS2 fusion oncoprotein, which is found in aggressive acute megakaryoblastic leukemia, confers megakaryocytic identity via the GLIS2 moiety while both ETO2 and GLIS2 domains are required to drive increased self-renewal properties. ETO2-GLIS2 directly binds DNA to control transcription of associated genes by upregulation of expression and interaction with the ETS-related ERG protein at enhancer elements. Importantly, specific interference with ETO2-GLIS2 oligomerization reverses the transcriptional activation at enhancers and promotes megakaryocytic differentiation, providing a relevant interface to target in this poor-prognosis pediatric leukemia.

Correlation Between Isocitrate Dehydrogenase Gene Aberrations and Prognosis of Patients with Acute Myeloid Leukemia: A Systematic Review and Meta-Analysis

Purpose: Whether isocitrate dehydrogenase (IDH) gene aberrations affected prognosis of patients with acute myeloid leukemia (AML) was controversial. Here, we conducted a meta-analysis to evaluate their prognostic value.Experimental Design: PubMed, Embase, Cochrane, and Chinese databases were searched to identify studies exploring how IDH gene aberrations affected AML outcome. Pooled HRs and relative risks (RR) were calculated, along with 95% confidence intervals (CI).Results: Thirty-three reports were included. IDH mutations seemed not to affect overall survival (OS: HR, 1.05; 95% CI, 0.89-1.23) and event-free survival (EFS: HR, 0.97; 95% CI, 0.80-1.18) when considered as a single factor, but improved accumulative incidence of relapse (CIR: HR, 1.44; 95% CI, 1.18-1.76) in patients with intermediate-risk karyotypes (IR-AML). However, IDH1 mutation conferred worse OS (HR, 1.17; 95% CI, 1.05-1.31) and EFS (HR, 1.29; 95% CI, 1.07-1.56), especially in patients with normal cytogenetics (OS: HR, 1.21; 95% CI, 1.01-1.46; EFS: HR, 1.56; 95% CI, 1.23-1.98). Prognosis of the IDH1 single-nucleotide polymorphism rs11554137 was also poor (OS: HR, 1.34; 95% CI, 1.03-1.75). IDH2 mutation improved OS (HR, 0.78; 95% CI, 0.66-0.93), particularly in IR-AML patients (OS: HR, 0.65; 95% CI, 0.49-0.86). The IDH2 (R140) mutation was associated with better OS among younger cases (HR, 0.64; 95% CI, 0.49-0.82). Treatment outcome was poor [RR for complete remission rates in IDH1 mutation: 1.21; 95% CI, 1.02-1.44; IDH2 (R172) mutation: 2.14; 95% CI, 1.61-2.85].Conclusions: Various subtypes of IDH mutations might contribute to different prognosis and be allowed to stratify IR-AML further. Clin Cancer Res; 23(15); 4511-22. ©2017 AACR.

Molecular and genetic alterations associated with therapy resistance and relapse of acute myeloid leukemia

Background

The majority of individuals with acute myeloid leukemia (AML) respond to initial chemotherapy and achieve a complete remission, yet only a minority experience long-term survival because a large proportion of patients eventually relapse with therapy-resistant disease. Relapse therefore represents a central problem in the treatment of AML. Despite this, and in contrast to the extensive knowledge about the molecular events underlying the process of leukemogenesis, information about the mechanisms leading to therapy resistance and relapse is still limited.

Purpose and content of review

Recently, a number of studies have aimed to fill this gap and provided valuable information about the clonal composition and evolution of leukemic cell populations during the course of disease, and about genetic, epigenetic, and gene expression changes associated with relapse. In this review, these studies are summarized and discussed, and the data reported in them are compiled in order to provide a resource for the identification of molecular aberrations recurrently acquired at, and thus potentially contributing to, disease recurrence and the associated therapy resistance. This survey indeed uncovered genetic aberrations with known associations with therapy resistance that were newly gained at relapse in a subset of patients. Furthermore, the expression of a number of protein coding and microRNA genes was reported to change between diagnosis and relapse in a statistically significant manner.

Conclusions

Together, these findings foster the expectation that future studies on larger and more homogeneous patient cohorts will uncover pathways that are robustly associated with relapse, thus representing potential targets for rationally designed therapies that may improve the treatment of patients with relapsed AML, or even facilitate the prevention of relapse in the first place.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0416-0) contains supplementary material, which is available to authorized users.

Karyotype plus NPM1 mutation status defines a group of elderly patients with AML (≥60 years) who benefit from intensive post-induction consolidation therapy

Although it is generally appreciated that a subset of elderly patients with acute myeloid leukemia (AML) may benefit from intensive consolidation, little is known about variables predicting such benefit. We analyzed 192 consecutive patients with de novo AML aged ≥60 years who were treated with intensive chemotherapy. About 115 patients (60%) achieved complete hematologic remission (CR). Among several parameters, the karyotype was the only independent variable predicting CR (P < 0.05). About 92% (105/115) of the CR-patients received up to four consolidation cycles of intermediate dose ARA-C. Median continuous CR (CCR) and disease-free survival (DFS) were 1.3 and 1.1 years, respectively. CCR, DFS, and survival at 5 years were 23%, 18%, and 15%, respectively. Only karyotype and mutated NPM1 (NPM1mut) were independent predictors of survival. NPM1mut showed a particular prognostic impact in patients with normal (CN) or non-monosomal (Mkneg) karyotype by Haemato-Oncology Foundation for Adults in the Netherlands (HOVON)-criteria, or intermediate karyotype by Southwest Oncology Group (SWOG)-criteria. The median CCR was 0.94, 1.6, 0.9, and 0.5 years for core-binding-factor, CN/Mkneg-NPM1mut, CN/Mkneg-NPM1-wild-type AML, and AML with monosomal karyotype, respectively, and the 5-year survival was 25%, 39%, 2%, and 0%, respectively (P < 0.05). Similar results (0.9, 1.5, 0.9, and 0.5 years) were obtained using modified SWOG criteria and NPM1 mutation status (P < 0.05). In summary, elderly patients with CN/Mkneg-NPM1mut or CBF AML can achieve long term CCR when treated with intensive induction and consolidation therapy whereas most elderly patients with CN/Mkneg-NPM1wt or Mkpos AML may not benefit from intensive chemotherapy. For these patients either hematopoietic-stem-cell-transplantation or alternative treatments have to be considered. Am. J. Hematol. 91:1239-1245, 2016. © 2016 Wiley Periodicals, Inc.

MLL-AF9 Expression in Hematopoietic Stem Cells Drives a Highly Invasive AML Expressing EMT-Related Genes Linked to Poor Outcome

To address the impact of cellular origin on acute myeloid leukemia (AML), we generated an inducible transgenic mouse model for MLL-AF9-driven leukemia. MLL-AF9 expression in long-term hematopoietic stem cells (LT-HSC) in vitro resulted in dispersed clonogenic growth and expression of genes involved in migration and invasion. In vivo, 20% LT-HSC-derived AML were particularly aggressive with extensive tissue infiltration, chemoresistance, and expressed genes related to epithelial-mesenchymal transition (EMT) in solid cancers. Knockdown of the EMT regulator ZEB1 significantly reduced leukemic blast invasion. By classifying mouse and human leukemias according to Evi1/EVI1 and Erg/ERG expression, reflecting aggressiveness and cell of origin, and performing comparative transcriptomics, we identified several EMT-related genes that were significantly associated with poor overall survival of AML patients.

Molecular therapy for acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a heterogeneous disease that is, in general, associated with a very poor prognosis. Multiple cytogenetic and molecular abnormalities that characterize different forms of AML have been used to better prognosticate patients and inform treatment decisions. Indeed, risk status in patients with this disease has classically been based on cytogenetic findings; however, additional molecular characteristics have been shown to inform risk assessment, including FLT3, NPM1, KIT, and CEBPA mutation status. Advances in sequencing technology have led to the discovery of novel somatic mutations in tissue samples from patients with AML, providing deeper insight into the mutational landscape of the disease. The majority of patients with AML (>97%) are found to have a clonal somatic abnormality on mutational profiling. Nevertheless, our understanding of the utility of mutation profiling in clinical practice remains incomplete and is continually evolving, and evidence-based approaches to application of these data are needed. In this Review, we discuss the evidence-base for integrating mutational data into treatment decisions for patients with AML, and propose novel therapeutic algorithms in the era of molecular medicine.

Midostaurin: an emerging treatment for acute myeloid leukemia patients

Acute myeloid leukemia (AML) is a hematologic malignancy that carries a poor prognosis and has garnered few treatment advances in the last few decades. Mutation of the internal tandem duplication (ITD) region of fms-like tyrosine kinase (FLT3) is considered high risk for decreased response and overall survival. Midostaurin is a Type III receptor tyrosine kinase inhibitor found to inhibit FLT3 and other receptor tyrosine kinases, including platelet-derived growth factor receptors, cyclin-dependent kinase 1, src, c-kit, and vascular endothelial growth factor receptor. In preclinical studies, midostaurin exhibited broad-spectrum antitumor activity toward a wide range of tumor xenografts, as well as an FLT3-ITD-driven mouse model of myelodysplastic syndrome (MDS). Midostaurin is orally administered and generally well tolerated as a single agent; hematologic toxicity increases substantially when administered in combination with standard induction chemotherapy. Clinical trials primarily have focused on relapsed/refractory AML and MDS and included single- and combination-agent studies. Administration of midostaurin to relapsed/refractory MDS and AML patients confers a robust anti-blast response sufficient to bridge a minority of patients to transplant. In combination with histone deacetylase inhibitors, responses appear comparable to historic controls, while the addition of midostaurin to standard induction chemotherapy may prolong survival in FLT3-ITD mutant patients. The response of some wild-type (WT)-FLT3 patients to midostaurin therapy is consistent with midostaurin’s ability to inhibit WT-FLT3 in vitro, and also may reflect overexpression of WT-FLT3 in those patients and/or off-target effects such as inhibition of kinases other than FLT3. Midostaurin represents a well-tolerated, easily administered oral agent with the potential to bridge mutant and WT-FLT3 AML patients to transplant and possibly deepen response to induction chemotherapy. Ongoing studies are investigating midostaurin’s role in pretransplant induction and posttransplant consolidation therapy.

Acute myeloid leukemia: advancing clinical trials and promising therapeutics

Recent progress in understanding the biology of acute myeloid leukemia (AML) and the identification of targetable driver mutations, leukemia specific antigens and signal transduction pathways has ushered in a new era of therapy. In many circumstances the response rates with such targeted or antibody-based therapies are superior to those achieved with standard therapy and with decreased toxicity. In this review we discuss novel therapies in AML with a focus on two major areas of unmet need: (1) single agent and combination strategies to improve frontline therapy in elderly patients with AML and (2) molecularly targeted therapies in the frontline and salvage setting in all patients with AML.

CD45RA, a specific marker for leukaemia stem cell sub-populations in acute myeloid leukaemia

Chemotherapy resistant leukaemic stem cells (LSC) are thought to be responsible for relapses after therapy in acute myeloid leukaemia (AML). Flow cytometry can discriminate CD34(+) CD38(-) LSC and normal haematopoietic stem cells (HSC) by using aberrant expression of markers and scatter properties. However, not all LSC can be identified using currently available markers, so new markers are needed. CD45RA is expressed on leukaemic cells in the majority of AML patients. We investigated the potency of CD45RA to specifically identify LSC and HSC and improve LSC quantification. Compared to our best other markers (CLL-1, also termed CLEC12A, CD33 and CD123), CD45RA was the most reliable marker. Patients with high percentages (>90%) of CD45RA on CD34(+) CD38(-) LSC have 1·69-fold higher scatter values compared to HSC (P < 0·001), indicating a more mature CD34(+) CD38(-) phenotype. Patients with low (<10%) or intermediate (10-90%) CD45RA expression on LSC showed no significant differences to HSC (1·12- and 1·15-fold higher, P = 0·31 and P = 0·44, respectively). CD45RA-positive LSC tended to represent more favourable cytogenetic/molecular markers. In conclusion, CD45RA contributes to more accurate LSC detection and is recommended for inclusion in stem cell tracking panels. CD45RA may contribute to define new LSC-specific therapies and to monitor effects of anti-LSC treatment.

Review: Aberrant EVI1 expression in acute myeloid leukaemia

Deregulated expression of the ecotropic virus integration site 1 (EVI1) gene is the molecular hallmark of therapy-resistant myeloid malignancies bearing chromosomal inv(3)(q21q26·2) or t(3;3)(q21;q26·2) [hereafter referred to as inv(3)/t(3;3)] abnormalities. EVI1 is a haematopoietic stemness and transcription factor with chromatin remodelling activity. Interestingly, the EVI1 gene also shows overexpression in 6-11% of adult acute myeloid leukaemia (AML) cases that do not carry any 3q aberrations. Deregulated expression of EVI1 is strongly associated with monosomy 7 and 11q23 abnormalities, which are known to be associated with poor response to treatment. However, EVI1 overexpression has been revealed as an important independent adverse prognostic marker in adult AML and defines distinct risk categories in 11q23-rearranged AML. Recently, important progress has been made in the delineation of the mechanism by which EVI1 becomes deregulated in inv(3)/t(3;3) as well as the cooperating mutations in this specific subset of AML with dismal prognosis.