Monoallelic CEBPA mutations in normal karyotype acute myeloid leukemia: independent favorable prognostic factor within NPM1 mutated patients

Impact of different CEBPA mutations on therapeutic outcome in acute myeloid leukemia

Biallelic mutations of the CEBPA gene (CEBPAbi) are generally associated with favorable prognosis in patients with acute myeloid leukemia (AML). Monoallelic mutations of the CEBPA gene in carboxy-terminal DNA-binding region (CEBPAsmbZIP) and amino-terminal transactivation domains (CEBPAsmTAD) indicate distinct clinical characteristics and therapeutic outcomes. However, further investigation is required to fully understand these differences. In this retrospective study, we enrolled 77 AML patients with CEBPA mutations, including 53 with CEBPAbi, 12 with CEBPAsmbZIP and 12 with CEBPAsmTAD. The clinical characteristics of the three CEBPAmut groups presented significant differences in age, FAB classification, hemoglobin level and platelet count at diagnosis. The CEBPAsmTAD group exhibited shorter 2-year overall survival (OS) and relapse-free survival (RFS) compared to the CEBPAbi group and CEBPAsmbZIP group in AML patients. The most common co-mutations observed in CEBPAmut AML patients were TET2 and GATA2, which had no effect on prognosis. 2-year RFS of 27 CEBPAmut AML patients who underwent allo-HSCT was better than those who did not. MRD3 positive was identified as an influencing factor for 2-year OS and RFS. Allo-HSCT was found to improve the prognosis of CEPBAmut AML patients with positive MRD3 and adverse co-mutations.

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).

Sporadic and Familial Acute Myeloid Leukemia with CEBPA Mutations

PURPOSE OF REVIEW

CCAAT enhancer binding protein A (CEBPA) gene mutation is one of the common genetic alterations in acute myeloid leukemia (AML), which can be associated with sporadic and familial AML.

RECENT FINDINGS

Due to the recent advances in molecular testing and the prognostic role of CEBPA mutation in AML, the definition for AML with CEBPA mutation (AML-CEBPA) has significantly changed. This review provides the rationale for the updates on classifications, and the impacts on laboratory evaluation and clinical management for sporadic and familial AML-CEBPA patients. In addition, minimal residual disease assessment post therapy to stratify disease risk and stem cell transplant in selected AML-CEBPA patients are discussed. Taken together, the recent progresses have shifted the definition, identification, and management of patients with AML-CEBPA.

Cytogenetics analysis as the central point of genetic testing in acute myeloid leukemia (AML): a laboratory perspective for clinical applications

Chromosomal abnormalities in acute myeloid leukemia (AML) have significantly contributed to scientific understanding of its molecular pathogenesis, which has aided in the development of therapeutic strategies and enhanced management of AML patients. The diagnosis, prognosis and treatment of AML have also rapidly transformed in recent years, improving initial response to treatment, remission rates, risk stratification and overall survival. Hundreds of rare chromosomal abnormalities in AML have been discovered thus far using chromosomal analysis and next-generation sequencing. As a result, the World Health Organization (WHO) has categorized AML into subgroups based on genetic, genomic and molecular characteristics, to complement the existing French-American classification which is solely based on morphology. In this review, we aim to highlight the most clinically relevant chromosomal aberrations in AML together with the technologies employed to detect these aberrations in laboratory settings.

Targeting C/EBPα overcomes primary resistance and improves the efficacy of FLT3 inhibitors in acute myeloid leukaemia

The outcomes of FLT3-ITD acute myeloid leukaemia (AML) have been improved since the approval of FLT3 inhibitors (FLT3i). However, approximately 30-50% of patients exhibit primary resistance (PR) to FLT3i with poorly defined mechanisms, posing a pressing clinical unmet need. Here, we identify C/EBPα activation as a top PR feature by analyzing data from primary AML patient samples in Vizome. C/EBPα activation limit FLT3i efficacy, while its inactivation synergistically enhances FLT3i action in cellular and female animal models. We then perform an in silico screen and identify that guanfacine, an antihypertensive medication, mimics C/EBPα inactivation. Furthermore, guanfacine exerts a synergistic effect with FLT3i in vitro and in vivo. Finally, we ascertain the role of C/EBPα activation in PR in an independent cohort of FLT3-ITD patients. These findings highlight C/EBPα activation as a targetable PR mechanism and support clinical studies aimed at testing the combination of guanfacine with FLT3i in overcoming PR and enhancing the efficacy of FLT3i therapy.

The correlation of next-generation sequencing-based genotypic profiles with clinicopathologic characteristics in NPM1-mutated acute myeloid leukemia

The purpose of this study was to analyze the association between next-generation sequencing (NGS) genotypic profiles and conventional clinicopathologic characteristics in patients with acute myeloid leukemia (AML) with NPM1 mutation (NPM1^mut). We selected 238 NPM1^mut patients with available NGS information on 112 genes related to blood diseases using the χ2 and Mann-Whitney U tests and a multivariable logistic model to analyze the correlation between genomic alterations and clinicopathologic parameters. Compared with the NPM1^mut/FLT3-ITD⁽⁻⁾ group, the NPM1^mut/FLT3-ITD⁽⁺⁾ group presented borderline frequent M5 morphology [78/143 (54.5%) vs. 64/95 (67.4%); P = 0.048], higher CD34- and CD7-positive rates (CD34: 20.6% vs. 47.9%, P < 0.001; CD7: 29.9% vs. 61.5%, P < 0.001) and a lack of favorable−/adverse-risk karyotypes (6.4% vs. 0%; P = 0.031). In the entire NPM1^mut cohort, 240 NPM1 mutants were identified, of which 10 (10/240, 4.2%) were missense types. When confining the analysis to the 205 cases with NPM1^mut insertions/deletions-type and normal karyotype, multivariable logistic analysis showed that FLT3-ITD was positively correlated with CD34 and CD7 expressions (OR = 5.29 [95% CI 2.64–10.60], P < 0.001; OR = 3.47 [95% CI 1.79–6.73], P < 0.001, respectively). Ras-pathway mutations were positively correlated with HLA-DR expression (OR = 4.05 [95% CI 1.70–9.63], P = 0.002), and KRAS mutations were negatively correlated with MPO expression (OR = 0.18 [95% CI 0.05–0.62], P = 0.007). DNMT3A-R882 was positively correlated with CD7 and HLA-DR expressions (OR = 3.59 [95% CI 1.80–7.16], P < 0.001; OR = 13.41 [95% CI 4.56–39.45], P < 0.001, respectively). DNMT3A mutation was negatively correlated with MPO expression (OR = 0.35 [95% CI 1.48–8.38], P = 0.004). TET2/IDH1 mutations were negatively correlated with CD34 and CD7 expressions (OR = 0.26 [95% CI 0.11–0.62], P = 0.002; OR = 0.30 [95% CI 0.14–0.62], P = 0.001, respectively) and positively correlated with MPO expression (OR = 3.52 [95% CI 1.48–8.38], P = 0.004). In conclusion, NPM1^mut coexisting mutations in signaling pathways (FLT3-ITD and Ras-signaling pathways) and methylation modifiers (DNMT3A and TET2/IDH1) are linked with the expressions of CD34, CD7, HLA-DR and MPO, thereby providing a mechanistic explanation for the immunophenotypic heterogeneity of this AML entity.

The clinical characteristics and prognosis of cytogenetically normal AML with single mutations of CEBPA

INTRODUCTION

CEBPA mutation is a common mutation in normal karyotype AML. CEBPAdm AML has been recognized as a separate entity, but there is still controversy to the prognosis of CEBPAsm patients.

METHODS

A total of 151 newly diagnosed cytogenetically normal AML patients treated at the Second Hospital Center of Shanxi Medical University from February 2017 to December 2019 were the subjects of the study. According to the number of mutations in the CEBPA gene, the patients were divided into three groups, CEBPAsm, CEBPAdm, and CEBPAwt patients. The clinical characteristics, gene mutations, response, and prognosis were retrospectively compared among the three groups.

RESULTS

CEBPAsm patients had lower hemoglobin values compared to CEBPAdm (P = .049). There was no statistical difference between the CEBPAsm cases and the CEBPAdm cases in the mutation types and the distribution of mutation regions (P > .050). Compared with CEBPAdm, cases with CEBPAsm were more likely associated with multiple other gene mutations (P = .023). Patients with CEBPAdm had a higher CR, ORR, and OS than those CEBPAwt (P < .050). CEBPAsm patients had a similar OS with CEBPAdm and CEBPAwt patients (P = .281). These CEBPAsm patients with VAF<30% had lower OS than the patients with VAF≥30%. FLT3-ITD mutations could reduce CEBPAsm patients' OS (P = .019).

CONCLUSION

Our data first highlighted the impact of CEBPAsm VAF on OS, and the results showed the lower the VAF was, the shorter the OS tended to. The VAF of CEBPAsm could provide specific significance in some extent for the prognosis of patients.

Chronic interleukin-1 exposure triggers selection for Cebpa-knockout multipotent hematopoietic progenitors

The early events that drive myeloid oncogenesis are not well understood. Most studies focus on the cell-intrinsic genetic changes and how they impact cell fate decisions. We consider how chronic exposure to the proinflammatory cytokine, interleukin-1β (IL-1β), impacts Cebpa-knockout hematopoietic stem and progenitor cells (HSPCs) in competitive settings. Surprisingly, we found that Cebpa loss did not confer a hematopoietic cell–intrinsic competitive advantage; rather chronic IL-1β exposure engendered potent selection for Cebpa loss. Chronic IL-1β augments myeloid lineage output by activating differentiation and repressing stem cell gene expression programs in a Cebpa-dependent manner. As a result, Cebpa-knockout HSPCs are resistant to the prodifferentiative effects of chronic IL-1β, and competitively expand. We further show that ectopic CEBPA expression reduces the fitness of established human acute myeloid leukemias, coinciding with increased differentiation. These findings have important implications for the earliest events that drive hematologic disorders, suggesting that chronic inflammation could be an important driver of leukemogenesis and a potential target for intervention.

The incidence and prognostic effect of Fms-like tyrosine kinase 3 gene internal tandem and nucleolar phosphoprotein 1 genes in acute myeloid leukaemia: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Molecular genotyping is an important prognostic role in acute myeloid leukemia (AML) patients. We aimed to design this meta-analysis to discuss the incidence and prognostic effect of nucleolar phosphoprotein 1 (NPM1) and Fms-like tyrosine kinase 3 gene internal tandem (FLT3-ITD) gene in AML patients.

METHODS

PubMed, Embase, Medline, and Cochrane library were systematically searched due to May 15, 2020. Four combinations of genotypes (FLT3-ITDneg/NPM1mut, FLT3-ITDpos/NPM1mut, FLT3-ITDneg/NPM1wt, FLT3-ITDpos/NPM1wt) were compared in association with the overall survival (OS) and leukemia-free survival (LFS) outcome, which expressed as pooled hazard ratio (HR) and 95% confidence intervals (CIs).

RESULTS

Twenty-eight studies were included in our study. The incidence of FLT3-ITDneg/NPM1mut, FLT3-ITDpos/NPM1mut, FLT3-ITDneg/NPM1wt, and FLT3-ITDpos/NPM1wt was 16%, 13%, 50%, and 10%, respectively. The patients with FLT3-ITDneg/NPM1mut gene may have the best OS and LFS when comparing with FLT3-ITDpos/NPM1mut (HR = 1.94 and 1.70, P < .01), FLT3-ITDneg/NPM1wt (HR = 1.57 and 2.09, P < .01), and FLT3-ITDpos/NPM1wt (HR = 2.25 and 2.84, P < .001).

CONCLUSION

AML patients with FLT3-ITDneg/NPM1mut gene type have the best survival outcome than the other 3 gene types, which should be an independent genotyping in AML classification.

Current and emerging molecular and epigenetic disease entities in acute myeloid leukemia and a critical assessment of their therapeutic modalities

Acute myeloid leukemia (AML) is the most frequently diagnosed acute leukemia, and its incidence increases with age. Although the etiology of AML remains unknown, exposure to genotoxic agents or some prior hematologic disorders could lead to the development of this condition. The pathogenesis of AML involves the development of malignant transformation of hematopoietic stem cells that undergo successive genomic alterations, ultimately giving rise to a full-blown disease. From the disease biology perspective, AML is considered to be extremely complex with significant genetic, epigenetic, and phenotypic variations. Molecular and cytogenetic alterations in AML include mutations in those subsets of genes that are involved in normal cell proliferation, maturation and survival, thus posing significant challenge to targeting these pathways without attendant toxicity. In addition, multiple malignant cells co-exist in the majority of AML patients. Individual subclones are characterized by unique genetic and epigenetic abnormalities, which contribute to the differences in their response to treatment. As a result, despite a dramatic progress in our understanding of the pathobiology of AML, not much has changed in therapeutic approaches to treat AML in the past four decades. Dose and regimen modifications with improved supportive care have contributed to improved outcomes by reducing toxicity-related side effects. Several drug candidates are currently being developed, including targeted small-molecule inhibitors, cytotoxic chemotherapies, monoclonal antibodies and epigenetic drugs. This review summarizes the current state of affairs in the pathobiological and therapeutic aspects of AML.

High IFITM3 expression predicts adverse prognosis in acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignancy caused by the uncontrolled and dysregulated clonal expansion of abnormal myeloid primordial cells. In general, the prognosis of AML remains poor despite new discoveries in its pathogenesis and treatment. It is crucial to find early and sensitive biomarkers and continue to explore active targeted treatments. Interferon-induced transmembrane protein (IFITM) family is an important part of the interferon signaling pathway and participate in the regulation of immune cell signaling, adhesion, cancer, and liver cell migration. However, the clinical and prognostic value of the IFITM family in AML has rarely been studied. We screened The Cancer Genome Atlas database and found 155 AML patients with IFITM family (IFITM1-5) expression data. In patients who only received chemotherapy, those with high IFITM3 expression had significantly shorter event-free survival (EFS) and overall survival (OS) than patients with low expression (all P < 0.05). Multivariate analysis demonstrated that high IFITM3 expression was an independent risk factor for EFS and OS in patients only received chemotherapy (all P < 0.05). In patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), however, all IFITM members had no impact on either EFS or OS. In conclusion, our study elucidated that high IFITM3 expression could be an adverse prognostic factor for AML, whose effect might be overcome by allo-HSCT.

Genomics-based Approach and Prognostic Stratification Significance of Gene Mutations in Intermediate-risk Acute Myeloid Leukemia

OBJECTIVE

Intermediate-risk acute myeloid leukemia (IR-AML), which accounts for a substantial number of AML cases, is highly heterogeneous. We systematically summarize the latest research progress on the significance of gene mutations for prognostic stratification of IR-AML.

DATA SOURCES

We conducted a systemic search from the PubMed database up to October, 2014 using various search terms and their combinations including IR-AML, gene mutations, mutational analysis, prognosis, risk stratification, next generation sequencing (NGS).

STUDY SELECTION

Clinical or basic research articles on NGS and the prognosis of gene mutations in IR-AML were included.

RESULTS

The advent of the era of whole-genome sequencing has led to the discovery of an increasing number of molecular genetics aberrations that involved in leukemogenesis, and some of them have been used for prognostic risk stratification. Several studies have consistently identified that some gene mutations have prognostic relevance, however, there are still many controversies for some genes because of lacking sufficient evidence. In addition, tumor cells harbor hundreds of mutated genes and multiple mutations often coexist, therefore, single mutational analysis is not sufficient to make accurate prognostic predictions. The comprehensive analysis of multiple mutations based on sophisticated genomic technologies has raised increasing interest in recent years.

CONCLUSIONS

NGS represents a pioneering and helpful approach to prognostic risk stratification of IR-AML patients. Further large-scale studies for comprehensive molecular analysis are needed to provide guidance and a theoretical basis for IR-AML prognostic stratification and clinical management.

Acute Myeloid Leukemia With Recurrent Genetic Abnormalities Other Than Translocations

OBJECTIVES

Session 2 of the workshop focused on cases of acute myeloid leukemia (AML) with gene mutations in the setting of a normal karyotype.

METHODS

Among 22 AML cases submitted, 14 had the NPM1 mutation, most also accompanied by mutations of other genes such as FLT3-ITD, DNMT3A, or, rarely, TP53; three cases had the heterozygous CEBPA mutation; and two cases had MYC amplification.

RESULTS

We explored prognostic implications of gene mutations such as DNMT3A, issues related to the classification of AML cases with the NPM1 mutation, and myelodysplasia-related changes arising from chronic myelomonocytic leukemia after a short latency interval. Disparate patterns of treatment response to targeted therapy using an FLT3 inhibitor, designated as cytotoxic or differentiation, and their genetic underpinnings were described. Finally, a minimal screening panel for gene mutations and the optimal approach for monitoring minimal residual disease were discussed.

CONCLUSIONS

In aggregate, this session highlighted the need for a refined molecular classification of AML as well as improved risk stratification based on systematic assessment for genetic alterations and their evolution over time.

Whole genome and transcriptome analysis of a novel AML cell line with a normal karyotype

Acute myeloid leukemia (AML) occurs when hematopoietic progenitor cells acquire genetic defects blocking the regulation of normal growth and differentiation. Although recurrent translocations have been identified in AML, almost half of adult AML patients present with a normal karyotype (NK-AML). While cell line models exist to study AML, they frequently have abnormal/unstable karyotypes, while primary cells from NK-AML patients are difficult to maintain in vitro. Here we provide a thorough molecular characterization of a recently established cell line, CG-SH, which has normal cytogenetics, representing a useful new model for NK-AML. Using high-throughput DNA sequencing, we first defined the genetic background of this cell line. In addition to identifying potentially deleterious SNVs in genes relevant to AML, we also found insertions in both GATA2 and EZH2, two genes previously linked to AML. We further characterized the growth of this model system in vitro with a cytokine mix that promotes faster cell growth. We assessed gene expression changes after the addition of cytokines to the culture media and found differential expression in genes implicated in proliferation, apoptosis and differentiation. Our results provide a detailed molecular characterization of genetic defects in this cell line derived from an NK-AML patient.

Favorable prognosis of biallelic CEBPA gene mutations in acute myeloid leukemia patients: a meta-analysis

OBJECTIVES

Increasing number of studies suggested that biallelic CEBPA (bi CEBPA) mutations were associated with favorable prognosis in patients with acute myeloid leukemia (AML), but the results remain inconclusive. We therefore present a meta-analysis to evaluate the prognostic value of bi CEBPA mutations in patients with AML.

METHODS

A comprehensive literature search was undertaken through August 2014 looking for eligible studies. Pooled hazard ratios (HRs) estimates and 95% confidence intervals (95% CIs) in overall survival (OS) and event-free survival (EFS) were used to calculate estimated effect.

RESULTS

Ten studies covering a total of 6219 subjects were included in this analysis. Overall, bi CEBPA mutations were associated with favorable clinical outcome in patients with AML (HR for EFS: 0.41, 95% CI: 0.32-0.52; for OS: 0.37, 95% CI: 0.27-0.50), in cytogenetically normal (CN)-AML (HR for EFS: 0.38, 95% CI: 0.29-0.49; for OS: 0.32, 95% CI: 0.23-0.43). When took the cohort of monoallelic CEBPA (mo CEBPA) mutated and wild-type CEBPA (wt CEBPA) AML as a reference group, bi CEBPA mutated AML also shown beneficial outcomes (HR for OS: 0.52, 95% CI: 0.37-0.72). No significant difference was found between mo CEBPA mutation and wt CEBPA in patients with AML or CN-AML (P > 0.05).

CONCLUSION

Bi CEBPA mutations in patients with AML are strongly associated with a favorable prognosis, which suggested that bi CEBPA mutations would potentially serve as a novel prognostic marker in AML.

Long-term follow-up of cytogenetically normal CEBPA-mutated AML

Background

The aim of this study was to analyze the long-term survival of AML patients with CEBPA mutations.

Patients and methods

We investigated 88 AML patients with a median age of 61 years and (1) cytogenetically normal AML (CN-AML), (2) monoallelic (moCEBPA) or biallelic (biCEBPA) CEBPA mutation, and (3) intensive induction treatment. 60/88 patients have been described previously with a shorter follow-up.

Results

Median follow-up time was 9.8 years (95% CI: 9.4-10.1 years) compared to 3.2 and 5.2 years in our former analyses. Patients with biCEBPA mutations survived significantly longer compared to those with moCEBPA (median overall survival (OS) 9.6 years vs. 1.7 years, p = 0.008). Patients ≤ 60 years and biCEBPA mutations showed a favorable prognosis with a 10-year OS rate of 81%.

Both, bi- and moCEBPA-mutated groups had a low early death (d60) rate of 7% and 9%, respectively. Complete remission (CR) rates for biCEBPA- and moCEBPA-mutated patients were 82% vs. 70% (p = 0.17). biCEBPA-mutated patients showed a longer relapse free survival (RFS) (median RFS 9.4 years vs. 1.5 years, p = 0.021) and a lower cumulative incidence of relapse (CIR) compared to moCEBPA-mutated patients. These differences in OS and RFS were confirmed after adjustment for known clinical and molecular prognostic factors.

Conclusions

In this long-term observation we confirmed the favorable prognostic outcome of patients with biCEBPA mutations compared to moCEBPA-mutated CN-AML. The high probability of OS (81%) in younger patients is helpful to guide intensity of postremission therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-014-0055-7) contains supplementary material, which is available to authorized users.

Prognostic implications of CEBPA mutations in pediatric acute myeloid leukemia: a report from the Japanese Pediatric Leukemia/Lymphoma Study Group

CCAAT/enhancer-binding protein alpha (CEBPA) mutations are a favorable prognostic factor in adult acute myeloid leukemia (AML) patients; however, few studies have examined their significance in pediatric AML patients. Here we examined the CEBPA mutation status and clinical outcomes of pediatric AML patients treated in the AML-05 study. We found that 47 (14.9%) of the 315 evaluable patients harbored mutations in CEBPA; 26 cases (8.3%) harbored a single mutation (CEBPA-single) and 21 (6.7%) harbored double or triple mutations (CEBPA-double). After excluding core-binding factor-AML cases, patients harboring CEBPA mutations showed better overall survival (OS; P=0.048), but not event-free survival (EFS; P=0.051), than wild-type patients. Multivariate analysis identified CEBPA-single and CEBPA-double as independent favorable prognostic factors for EFS in the total cohort (hazard ratio (HR): 0.47 and 0.33; P=0.02 and 0.01, respectively). CEBPA-double was also an independent favorable prognostic factor for OS (HR: 0.30; P=0.04). CEBPA-double remained an independent favorable factor for EFS (HR: 0.28; P=0.04) in the normal karyotype cohort. These results suggest that CEBPA mutations, particularly CEBPA-double, are an independent favorable prognostic factor in pediatric AML patients, which will have important implications for risk-stratified therapy.

The role of different genetic subtypes of CEBPA mutated AML

The prognostic impact of mutations in the CCAAT/enhancer binding protein α (CEBPA) gene was evaluated in the context of concomitant molecular mutations and cytogenetic aberrations in acute myeloid leukemia (AML). CEBPA was screened in a cohort of 2296 adult AML cases. Of 244 patients (10.6%) with CEBPA mutations, 140 cases (6.1%) were single-mutated (CEBPAsm) and 104 cases (4.5%) were double-mutated (CEBPAdm). Cytogenetic analysis revealed normal karyotype in 172/244 (70.5%) of CEBPAmut cases, whereas in 72/244 cases (29.5%) at least one cytogenetic aberration was detected. Concurrent molecular mutations were seen less frequently in CEBPAdm than in CEBPAsm AML cases (69.2% vs 88.6% P<0.001). In detail, the spectrum of concurrent mutations was different in both groups with the frequent occurrence of GATA1 and WT1 mutations in CEBPAdm patients. In contrast, FLT3-ITD, NPM1, ASXL1 and RUNX1 mutations were detected more frequently in CEBPAsm cases. Favorable outcome was restricted to CEBPAdm cases and remained an independent prognostic factor for a favorable outcome in multivariate analysis (hazard ratio: 0.438, P=0.020). Outcome in CEBPAsm cases strongly depended on concurrent FLT3-ITD. In conclusion, we propose that only CEBPAdm should be considered as an entity in the WHO classification of AML and should be clearly distinguished from CEBPAsm AML.

CEBPA single mutation can be a possible favorable prognostic indicator in NPM1 and FLT3-ITD wild-type acute myeloid leukemia patients with intermediate cytogenetic risk

The aim of this study was to evaluate the prognostic impact of CEBPA single mutation in acute myeloid leukemia (AML) patients with intermediate cytogenetic risk. CEBPA single and double mutations were detected in 11 (9.7%) and 17 (15.1%) of 113 NPM1 wild-type patients, but no CEBPA mutations were detected in a group of 44 NPM1 mutated patients. Among patients with NPM1/FLT3-ITD wild-type, those with CEBPA double mutations (P=0.013 and 0.007 for overall survival and relapse-free survival, respectively) or a single mutation (P=0.039 and 0.020 for overall survival and relapse-free survival, respectively) demonstrated a favorable prognosis compared with CEBPA wild-type patients. Subsequent multivariate analysis confirmed the favorable prognostic impact of CEBPA single and double mutations. Despite the low statistical power of this study due to the small number of patients, our preliminary data suggest that CEBPA single mutation may be associated with favorable clinical outcomes in NPM1/FLT3-ITD wild-type AML patients with intermediate cytogenetic risk.

The Impact of FLT3 Mutations on the Development of Acute Myeloid Leukemias

The development of the genetic studies on acute myeloid leukemias (AMLs) has led to the identification of some recurrent genetic abnormalities. Their discovery was of fundamental importance not only for a better understanding of the molecular pathogenesis of AMLs, but also for the identification of new therapeutic targets. In this context, it is essential to identify AML-associated “driver” mutations, which have a causative role in leukemogenesis. Evidences accumulated during the last years indicate that activating internal tandem duplication mutations in FLT3 (FLT3-ITD), detected in about 20% of AMLs, represents driver mutations and valid therapeutic targets in AMLs. Furthermore, the screening of FLT3-ITD mutations has also considerably helped to improve the identification of more accurate prognostic criteria and of the therapeutic selection of patients.

CD34 expression predicts an adverse outcome in patients with NPM1-positive acute myeloid leukemia

Patients with acute myeloid leukemia (AML) harboring an NPM1 mutation exhibit a heterogeneous clinical outcome. Recent studies have shown that the absence of FLT3 internal tandem duplication (FLT3-ITD) mutation confers a favorable prognosis in NPM1-positive AML. However, the prognostic impact of immunophenotypes in this subgroup remains unclear. In this study, FLT3 mutation status and immunophenotypic profile of 85 NPM1-positive patients with de novo AML were retrospectively analyzed and correlated with their clinical features and survival outcomes. Univariate analysis detected 5 markers with prognostic relevance: older age (≥60 years), high white blood cell (WBC) count (>30 × 10(9)/L), FLT3-ITD, CD7, and CD34 expression. Multivariate analysis showed that high WBC count was the only independent predictor of a lower complete remission rate (P = .019). Older age (P = .035), high WBC count (P = .008), FLT3-ITD (P = .012), and CD34 expression (P = .006) were independent predictors of a shorter event-free survival (EFS). High WBC count (P = .014), FLT3-ITD (P = .005), and CD34 expression (P = .047) were independent predictors of a shorter overall survival (OS). Furthermore, based on FLT3-ITD status in NPM1 mutation-positive patients, we showed that both high WBC and CD34 expression conferred a poor EFS (P = .010 and P = .016, respectively) and OS (P = .032 and P = .001, respectively) in the FLT3-ITD-negative group, whereas high WBC predicted a poor EFS (P = .016) and OS (P = .027) in the FLT3-ITD-positive group. Our results confirm the prognostic value of assessing FLT3-ITD mutations in NPM1-positive AML and identify the adverse prognostic impact of high WBC and CD34 expression in this subgroup of AML.

The clinically relevant pharmacogenomic changes in acute myelogenous leukemia

Acute myelogenous leukemia (AML) is an extremely heterogeneous neoplasm with several clinical, pathological, genetic and molecular subtypes. Combinations of various doses and schedules of cytarabine and different anthracyclines have been the mainstay of treatment for all forms of AMLs in adult patients. Although this combination, with the addition of an occasional third agent, remains effective for treatment of some young-adult patients with de novo AML, the prognosis of AML secondary to myelodysplastic syndromes or myeloproliferative neoplasms, treatment-related AML, relapsed or refractory AML, and AML that occurs in older populations remains grim. Taken into account the heterogeneity of AML, one size does not and should not be tried to fit all. In this article, the authors review currently understood, applicable and relevant findings related to cytarabine and anthracycline drug-metabolizing enzymes and drug transporters in adult patients with AML. To provide a prime-time example of clinical applicability of pharmacogenomics in distinguishing a subset of patients with AML who might be better responders to farnesyltransferase inhibitors, the authors also reviewed findings related to a two-gene transcript signature consisting of high RASGRP1 and low APTX, the ratio of which appears to positively predict clinical response in AML patients treated with farnesyltransferase inhibitors.