ASXL1 mutations in younger adult patients with acute myeloid leukemia: a study by the German-Austrian Acute Myeloid Leukemia Study Group

Research progress on gene mutations and drug resistance in leukemia

Leukemia is a type of blood cancer characterized by the uncontrolled growth of abnormal cells in the bone marrow, which replace normal blood cells and disrupt normal blood cell function. Timely and personalized interventions are crucial for disease management and improving survival rates. However, many patients experience relapse following conventional chemotherapy, and increasing treatment intensity often fails to improve outcomes due to mutated gene-induced drug resistance in leukemia cells. This article analyzes the association of gene mutations and drug resistance in leukemia. It explores genetic abnormalities in leukemia, highlighting recently identified mutations affecting signaling pathways, cell apoptosis, epigenetic regulation, histone modification, and splicing mechanisms. Additionally, the article discusses therapeutic strategies such as molecular targeting of gene mutations, alternative pathway targeting, and immunotherapy in leukemia. These approaches aim to combat specific drug-resistant mutations, providing potential avenues to mitigate leukemia relapse. Future research with these strategies holds promise for advancing leukemia treatment and addressing the challenges of drug-resistant mutations to improve patient outcomes.

Comprehensive genomic characterization of hematologic malignancies at a pediatric tertiary care center

Despite the increasing availability of comprehensive next generation sequencing (NGS), its role in characterizing pediatric hematologic malignancies remains undefined. We describe findings from comprehensive genomic profiling of hematologic malignancies at a pediatric tertiary care center. Patients enrolled on a translational research protocol to aid in cancer diagnosis, prognostication, treatment, and detection of cancer predisposition. Disease-involved samples underwent exome and RNA sequencing and analysis for single nucleotide variation, insertion/deletions, copy number alteration, structural variation, fusions, and gene expression. Twenty-eight patients with hematologic malignancies were nominated between 2018-2021. Eighteen individuals received both germline and somatic sequencing; two received germline sequencing only. Germline testing identified patients with cancer predisposition syndromes and non-cancer carrier states. Fifteen patients (15/18, 83%) had cancer-relevant somatic findings. Potential therapeutic targets were identified in seven patients (7/18, 38.9%); three (3/7, 42.9%) received targeted therapies and remain in remission an average of 47 months later.

Epigenetic-modifying agents: The potential game changers in the treatment of hematologic malignancies

Hematologic malignancies are lethal diseases arising from accumulated leukemic cells with substantial genetic or epigenetic defects in their natural development. Epigenetic modifications, including DNA methylation and histone modifications, are critical in hematologic malignancy formation, propagation, and treatment response. Both mutations and aberrant recruitment of epigenetic modifiers are reported in different hematologic malignancies, which regarding the reversible nature of epigenetic regulations, make them a potential target for cancer treatment. Here, we have first outlined a comprehensive overview of current knowledge related to epigenetic regulation's impact on the development and prognosis of hematologic malignancies. Furthermore, we have presented an updated overview regarding the current status of epigenetic-based drugs in hematologic malignancies treatment. And finally, discuss current challenges and ongoing clinical trials based on the manipulation of epigenetic modifies in hematologic malignancies.

Human ASXL1-Mutant Hematopoiesis Is Driven by a Truncated Protein Associated with Aberrant Deubiquitination of H2AK119

Mutations in additional sex combs like 1 (ASXL1) confer poor prognosis both in myeloid malignancies and in premalignant clonal hematopoiesis (CH). However, the mechanisms by which these mutations contribute to disease initiation remain unresolved, and mutation-specific targeting has remained elusive. To address this, we developed a human disease model that recapitulates the disease trajectory from ASXL1-mutant CH to lethal myeloid malignancy. We demonstrate that mutations in ASXL1 lead to the expression of a functional, truncated protein and determine that truncated ASXL1 leads to global redistribution of the repressive chromatin mark H2AK119Ub, increased transposase-accessible chromatin, and activation of both myeloid and stem cell gene-expression programs. Finally, we demonstrate that H2AK119Ub levels are tied to truncated ASXL1 expression levels and leverage this observation to demonstrate that inhibition of the PRC1 complex might be an ASXL1-mutant-specific therapeutic vulnerability in both premalignant CH and myeloid malignancy.

SIGNIFICANCE

Mutant ASXL1 is a common driver of CH and myeloid malignancy. Using primary human HSPCs, we determine that truncated ASXL1 leads to redistribution of H2AK119Ub and may affect therapeutic vulnerability to PRC1 inhibition.

Acute Myeloid Leukemia and Next-Generation Sequencing Panels for Diagnosis: A Comprehensive Review

Acute myeloid leukemia (AML) is a genetically heterogeneous clonal disorder characterized by the accumulation of acquired somatic genetic alterations in hematopoietic progenitor cells, which alter the normal mechanisms of self-renewal, proliferation, and differentiation. Due to significant technological advancements in sequencing technologies in the last 2 decades, classification and prognostic scoring of AML has been refined, and multiple guidelines are now available for the same. The authors have tried to summarize, latest guidelines for AML diagnosis, important markers associated, epigenetics markers, various AML fusions and their importance, etc. Review of literature suggests lack of study or comprehensive information about current NGS panels for AML diagnosis, genes and fusions covered, their technical know-how, etc. To solve this issue, the authors have tried to present detailed review about currently in use next-generation sequencing myeloid panels and their offerings.

Comprehensive genomic profiling reveals molecular subsets of ASXL1-mutated myeloid neoplasms

A large-scale genomic analysis of patients with ASXL1-mutated myeloid disease has not been performed to date. We reviewed comprehensive genomic profiling results from 6043 adults to characterize clinicopathologic features and co-mutation patterns by ASXL1 mutation status. ASXL1 mutations occurred in 1414 patients (23%). Mutation co-occurrence testing revealed strong co-occurrence (p < 0.01) between mutations in ASXL1 and nine genes (SRSF2, U2AF1, RUNX1, SETBP1, EZH2, STAG2, CUX1, CSF3R, CBL). Further analysis of patients with these co-mutations yielded several novel findings. Co-mutation patterns supported that ASXL1/SF3B1 co-mutation may be biologically distinct from ASXL1/non-SF3B1 spliceosome co-mutation. In AML, ASXL1/SRSF2 co-mutated patients frequently harbored STAG2 mutations (42%), which were dependent on the presence of both ASXL1 and SRSF2 mutation (p < 0.05). STAG2 and SETBP1 mutations were also exclusive in ASXL1/SRSF2 co-mutated patients and associated with divergent chronic myeloid phenotypes. Our findings support that certain multi-mutant genotypes may be biologically relevant in ASXL1-mutated myeloid disease.

Prognostic significance of ASXL1 mutations in acute myeloid leukemia: A systematic review and meta-analysis

Background

Although genetic mutations in additional sex-combs-like 1 (ASXL1) are prevalent in acute myeloid leukemia (AML), their exact impact on the AML prognosis remains uncertain. Hence, the present article was carried out to explore the prognostic importance of ASXL1 mutations in AML.

Methods

We thoroughly searched electronic scientific databases to find eligible papers. Twenty-seven studies with an overall number of 8,953 participants were selected for the current systematic review. The hazard ratio (HR) and 95% confidence interval (CI) for overall survival (OS), event-free survival (EFS), and relapse-free survival (RFS) were extracted from all studies with multivariate or univariate analysis. Pooled HRs and p-values were also calculated as a part of our work.

Results

The pooled HR for OS in multivariable analysis indicated that ASXL1 significantly diminished survival in AML patients (pooled HR: 1.67; 95% CI: 1.342-2.091).

Conclusions

ASXL1 mutations may confer a poor prognosis in AML. Hence, they may be regarded as potential prognostic factors. However, more detailed studies with different ASXL1 mutations are suggested to shed light on this issue.

Prognosis and risk factors for ASXL1 mutations in patients with newly diagnosed acute myeloid leukemia and myelodysplastic syndrome

OBJECTIVE

The objective of the study was to determine the prognosis and risk factors for additional sex combs like 1 (ASXL1) mutations in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

POPULATION AND METHODS

This retrospective study enrolled 219 adult patients with newly diagnosed AML and MDS, who were treated in West China Hospital from October 2018 to January 2022. The primary clinical outcome was evaluated by overall survival (OS) followed up to January 2023. Kaplan-Meier analysis and Cox multivariate regression analysis were performed to identify potential prognostic parameters in patients with ASXL1 mutations (mt).

RESULTS

A total of 34 (15.53%) ASXL1mt were detected, which occurred more frequently in the elderly and MDS cohorts (p < 0.001). Significantly lower blasts% (p < 0.001) and higher frequencies of mutant RUNX1, SRSF2, STAG2, EZH2, and SETBP1 (p < 0.02) were observed in the ASXL1mt cohort. Patients with ASXL1mt manifested with a worse complete remission rate (p = 0.011), and an inferior OS was shown in subgroups with MDS, co-mutations of RUNX1, SRSF2, or NRAS, as well as mutations in G646W (p < 0.05). Multivariate analysis considering age, diagnosis, co-mutations, and mutation site confirmed an independently adverse prognosis of mutations in G646W (HR = 4.302, 95% CI: 1.150-16.097) or RUNX1 co-mutations (HR = 4.620, 95% CI: 1.385-15.414) in the ASXL1mt cohort.

CONCLUSION

Our study indicated that mutations in G646W or RUNX1 co-mutations are closely associated with a dismal clinical outcome in patients with AML and MDS harboring ASXL1mt. Considering the poor prognosis and risk factors in patients with ASXL1mt, more available treatments should be pursued.

Prevalence and Prognosis of Secondary Genetic Aberrations Among Patients With Core Binding Factor Acute Myeloid Leukemia: A Mitelman Database Analysis

Background

Core binding factor acute myeloid leukemia (CBF-AML) comprises t(8;21) and inv(16) and usually has a favorable prognosis. However, a wide spectrum of secondary genetic aberrations has been shown to be associated with worse outcomes with respect to overall survival (OS) and relapse. We aimed to identify secondary molecular and chromosomal aberrations within each group of CBF-AML, i.e., t(8;21) and inv(16), and to evaluate their prognosis with OS.

Methods

Using the Mitelman Database of Chromosome Aberrations and Gene Fusions in Cancer, we analyzed 193 cases of CBF-AML reported between 2011 and 2021. We conducted a survival analysis to determine the 5-year OS, and we conducted univariate and multivariate Cox regression to identify independent genetic factors related to OS.

Results

Among the 193 cases with CBF-AML, structural and numerical chromosome rearrangements were 25.9% and 40.9%, respectively, and secondary genetic mutations were 54.9%. The 5-year OS for the presence of del(7) and trisomy 22 was significantly worse. NRAS mutations had a worse 5-year OS in the t(8;21) group in the univariate analysis but showed no significant difference in the multivariate analysis.

Conclusions

CBF-AML has heterogeneous cytogenetic characteristics but no difference in the 5-year OS between the inv(16) and t(8;21) groups. Finally, the presence of del(7), trisomy 22 and NRAS mutations showed a potential prognostic impact in CBF-AML patients. Secondary genetic findings may need to be identified to determine its association to a worse prognosis, and in the future develop better targeted therapies in patients with CBF-AML.

Molecular regulators of HOXA9 in acute myeloid leukemia

Dysregulation of the oncogenic transcription factor HOXA9 is a prominent feature for most aggressive acute myeloid leukemia cases and a strong indicator of poor prognosis in patients. Leukemia subtypes with hallmark overexpression of HOXA9 include those carrying MLL gene rearrangements, NPM1c mutations, and other genetic alternations. A growing body of evidence indicates that HOXA9 dysregulation is both sufficient and necessary for leukemic transformation. The HOXA9 mRNA and protein regulation includes multilayered controls by transcription factors (such as CDX2/4 and USF2/1), epigenetic factors (such as MLL-menin-LEDGF, DOT1L, ENL, HBO1, NPM1c-XPO1, and polycomb proteins), microRNAs (such as miR-126 and miR-196b), long noncoding RNAs (such as HOTTIP), three-dimensional chromatin interactions, and post-translational protein modifications. Recently, insights into the dynamic regulation of HOXA9 have led to an advanced understanding of the HOXA9 regulome and provided new cancer therapeutic opportunities, including developing inhibitors targeting DOT1L, menin, and ENL proteins. This review summarizes recent advances in understanding the molecular mechanisms controlling HOXA9 regulation and the pharmacological approaches that target HOXA9 regulators to treat HOXA9-driven acute myeloid leukemia.

Impact of mutations in epigenetic modifiers in acute myeloid leukemia: A systematic review and meta-analysis

This is a systematic review and meta-analysis evaluating the prognostic significance of epigenetic mutations on the overall survival (OS) in Acute Myeloid Leukemia (AML). We searched for studies evaluating epigenetic mutations in AML (up to November 2018) in PubMed, Trip database and Cochrane library. Hazard ratio (HR) of outcomes were extracted, and random-effects model was used to pool the results. A total of 10,002 citations were retrieved from the search strategy; 42 articles were identified for the meta-analysis (ASXL1 = 7, TET2 = 8, DNMT3A = 12, IDH =15), with fair to good-quality studies. The pooled HR was 1.88 (95% CI: 1.49-2.36) for ASXL1 mutation, 1.39 (95% CI: 1.18-1.63) for TET2 mutation, 1.35 (95% CI 1.16-1.56) for DNMT3a and 1.54 (95% CI: 1.15-2.06) for IDH mutation. However, there was a substantial heterogeneity in the DNMT3a and IDH studies. In conclusion epigenetic mutations in ASXL1, TET2, DNMT3a and IDH adversely impact OS in patients with AML albeit with considerable heterogeneity and possibly publication bias. Further studies are required to address these limitations.

High early death rates, treatment resistance, and short survival of Black adolescents and young adults with AML

Survival of patients with acute myeloid leukemia (AML) is inversely associated with age, but the impact of race on outcomes of adolescent and young adult (AYA; range, 18-39 years) patients is unknown. We compared survival of 89 non-Hispanic Black and 566 non-Hispanic White AYA patients with AML treated on frontline Cancer and Leukemia Group B/Alliance for Clinical Trials in Oncology protocols. Samples of 327 patients (50 Black and 277 White) were analyzed via targeted sequencing. Integrated genomic profiling was performed on select longitudinal samples. Black patients had worse outcomes, especially those aged 18 to 29 years, who had a higher early death rate (16% vs 3%; P=.002), lower complete remission rate (66% vs 83%; P=.01), and decreased overall survival (OS; 5-year rates: 22% vs 51%; P<.001) compared with White patients. Survival disparities persisted across cytogenetic groups: Black patients aged 18 to 29 years with non-core-binding factor (CBF)-AML had worse OS than White patients (5-year rates: 12% vs 44%; P<.001), including patients with cytogenetically normal AML (13% vs 50%; P<.003). Genetic features differed, including lower frequencies of normal karyotypes and NPM1 and biallelic CEBPA mutations, and higher frequencies of CBF rearrangements and ASXL1, BCOR, and KRAS mutations in Black patients. Integrated genomic analysis identified both known and novel somatic variants, and relative clonal stability at relapse. Reduced response rates to induction chemotherapy and leukemic clone persistence suggest a need for different treatment intensities and/or modalities in Black AYA patients with AML. Higher early death rates suggest a delay in diagnosis and treatment, calling for systematic changes to patient care.

Contemporary evaluation of acute myeloid leukemia patients with long-term survival exceeding five years

OBJECTIVES

Define clinical and laboratory attributes of acute myeloid leukemia (AML) patients with long-term survival exceeding five years and compare them with AML patients succumbing to disease within two years of diagnosis.

METHODS

A retrospective analysis of AML patients alive at least five years from the time of initial diagnosis. Baseline clinical data were compared with patients who died within two years of diagnosis.

RESULTS

The long-term cohort consisted of 93 patients treated in 2007-2016 with a median follow-up duration of 7.7 years (range 5-13.6 years). European LeukemiaNet (ELN) 2017 favorable risk patients accounted for 60% of the cohort. All long-term survivors achieved remission following induction chemotherapy. Multivariate analysis showed that compared with 132 patients experiencing death within 2 years of diagnosis, long term survivors were more likely to be of younger age [odds ratio (OR), 0.92; 95% confidence interval (CI), 0.9-0.95; p<0.001], have a lower initial WBC count (OR, 0.58; 95% CI, 0.43-0.79; p=0.0004), undergo an allogeneic stem cell transplantation (OR, 7.95; 95% CI, 3.07-20.59; p<0.0001), and harbor favorable risk cytogenetics (OR, 0.03; 95% CI, 0.006-0.23; p=0.0004).

CONCLUSIONS

Long term survival of AML is seen in a distinct demographic and biologic patient subset.

Evaluating the frequency, prognosis and survival of RUNX1 and ASXL1 mutations in patients with acute myeloid leukaemia in northeastern Iran

To evaluate the frequency and prognosis of runt‐related transcription factor 1 (RUNX1) and additional sex combs like‐1 (ASXL1) mutations in acute myeloid leukaemia (AML) patients in northeastern Iran. This cross‐sectional study was performed on 40 patients with AML (including 35 patients with denovo AML and five patients with secondary AML) from February 2018 to February 2021. All patients were followed up for 36 months. We evaluated the frequency and survival rate of RUNX1 and ASXL1 mutations in AML patients. To detect mutations, peripheral blood samples and bone marrow aspiration were taken from all participants. One male patient (2.5%) had RUNX1 mutations and four cases (10%; 3 females vs. 1 male) had ASXL1 mutations. The survival rates of AML patients after 1, 3, 6, 9, 12, 24 and 36 months were 98%, 90%, 77%, 62%, 52%, 27% and 20%, respectively. There was a significant relationship between the occurrence of ASXL1 mutations and the survival of patients with AML (p = 0.027). Also, there was a significant relationship between the incidence of death and haemoglobin levels in patients with AML (p = 0.045). Thus, with an increase of one unit in patients' haemoglobin levels, the risk of death is reduced by 16.6%. Patients with AML had a high mortality rate, poor therapy outcome and low survival rate. ASXL1 and RUNX1 mutations are associated with a worse prognosis in patients with newly diagnosed AML. Also, we witnessed that the prevalence of ASXL1 to RUNX1 mutations was higher in northeastern Iran compared with other regions.

The characteristics and clinical prognosis analysis of ASXL1 mutations in Chinese adult patients with primary cytogenetically normal acute myeloid leukemia by next-generation sequencing

We analyzed 156 adult patients with primary cytogenetically normal AML for ASXL1 mutations and co-mutations using targeted next-generation sequencing with a panel of 34 genes associated with myeloid neoplasms. ASXL1^mut were identified in 15(10%) patients, more frequent at an older age (≥60years) (p = .014), and had significant associations with co-mutations in TET2, KIT, CBL and SRSF2, whereas inversely correlated to NPM1 and CEBPA mutations. ASXL1^mut clustered in ELN2017 intermediate-risk group (p = .028). In the context of intermediate-risk, ASXL1^mut had a worse overall survival(OS) (p = .038) and Relapse-free survival(RFS) (p = .016) than ASXL1^wt. When coexisting DNMT3A or TET2 mutations, ASXL1^mut/DNMT3A^mut genetype revealed a superior OS than ASXL1^mut/DNMT3A^wt (p = .027), and ASXL1^mut/TET2^mut confered a worse RFS than ASXL1^mut/TET2^wt (p = .031). No significant prognosis impact of VAF (a cutoff value of 30%) and clone ranks of ASXL1^mut were observed in this corhort. Our study provided a new understanding of characteristics of ASXL1^mut AML.

Clonal hematopoiesis: Mutation-specific adaptation to environmental change

Clonal hematopoiesis of indeterminate potential (CHIP) describes a widespread expansion of genetically variant hematopoietic cells that increases exponentially with age and is associated with increased risks of cancers, cardiovascular disease, and other maladies. Here, we discuss how environmental contexts associated with CHIP, such as old age, infections, chemotherapy, or cigarette smoking, alter tissue microenvironments to facilitate the selection and expansion of specific CHIP mutant clones. Further, we consider major remaining gaps in knowledge, including intrinsic effects, clone size thresholds, and factors affecting clonal competition, that will determine future application of this field in transplant and preventive medicine.

Molecular Classification and Overcoming Therapy Resistance for Acute Myeloid Leukemia with Adverse Genetic Factors

The European LeukemiaNet (ELN) criteria define the adverse genetic factors of acute myeloid leukemia (AML). AML with adverse genetic factors uniformly shows resistance to standard chemotherapy and is associated with poor prognosis. Here, we focus on the biological background and real-world etiology of these adverse genetic factors and then describe a strategy to overcome the clinical disadvantages in terms of targeting pivotal molecular mechanisms. Different adverse genetic factors often rely on common pathways. KMT2A rearrangement, DEK-NUP214 fusion, and NPM1 mutation are associated with the upregulation of HOX genes. The dominant tyrosine kinase activity of the mutant FLT3 or BCR-ABL1 fusion proteins is transduced by the AKT-mTOR, MAPK-ERK, and STAT5 pathways. Concurrent mutations of ASXL1 and RUNX1 are associated with activated AKT. Both TP53 mutation and mis-expressed MECOM are related to impaired apoptosis. Clinical data suggest that adverse genetic factors can be found in at least one in eight AML patients and appear to accumulate in relapsed/refractory cases. TP53 mutation is associated with particularly poor prognosis. Molecular-targeted therapies focusing on specific genomic abnormalities, such as FLT3, KMT2A, and TP53, have been developed and have demonstrated promising results.

Epigenetic modifications and targeted therapy in pediatric acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematological malignancy resulting from the genetic alterations and epigenetic dysregulations of the hematopoietic progenitor cells. One-third of children with AML remain at risk of relapse even though outcomes have improved in recent decades. Epigenetic dysregulations have been identified to play a significant role during myeloid leukemogenesis. In contrast to genetic changes, epigenetic modifications are typically reversible, opening the door to the development of epigenetic targeted therapy. In this review, we provide an overview of the landscape of epigenetic alterations and describe the current progress that has been made in epigenetic targeted therapy, and pay close attention to the potential value of epigenetic abnormalities in the precision and combinational therapy of pediatric AML.

Murine Models of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a phenotypically and genetically heterogeneous hematologic malignancy. Extensive sequencing efforts have mapped the genomic landscape of adult and pediatric AML revealing a number of biologically and prognostically relevant driver lesions. Beyond identifying recurrent genetic aberrations, it is of critical importance to fully delineate the complex mechanisms by which they contribute to the initiation and evolution of disease to ultimately facilitate the development of targeted therapies. Towards these aims, murine models of AML are indispensable research tools. The rapid evolution of genetic engineering techniques over the past 20 years has greatly advanced the use of murine models to mirror specific genetic subtypes of human AML, define cell-intrinsic and extrinsic disease mechanisms, study the interaction between co-occurring genetic lesions, and test novel therapeutic approaches. This review summarizes the mouse model systems that have been developed to recapitulate the most common genomic subtypes of AML. We will discuss the strengths and weaknesses of varying modeling strategies, highlight major discoveries emanating from these model systems, and outline future opportunities to leverage emerging technologies for mechanistic and preclinical investigations.

Molecular Pathogenesis of BCR-ABL-Negative Atypical Chronic Myeloid Leukemia

Atypical chronic myeloid leukemia is a rare disease whose pathogenesis has long been debated. It currently belongs to the group of myelodysplastic/myeloproliferative disorders. In this review, an overview on the current knowledge about diagnosis, prognosis, and genetics is presented, with a major focus on the recent molecular findings. We describe here the molecular pathogenesis of the disease, focusing on the mechanisms of action of the main mutations as well as on gene expression profiling. We also present the treatment options focusing on emerging targeted therapies.

Risk factors affect accurate prognosis in ASXL1-mutated acute myeloid leukemia

Background

The epigenetic regulator additional sex combs-like 1 (ASXL1) is an adverse prognostic factor in acute myeloid leukemia (AML). However, the mutational spectrum and prognostic factors of ASXL1-mutated (ASXL1+) AML are largely unknown. We aim to evaluate the risk factors influencing the prognosis of ASXL1+ AML.

Methods

We performed next-generation sequencing (NGS) in 1047 cases of de novo AML and discovered 91 ASXL1+ AML (8.7%). The Log-Rank test and Kaplan-Meier were used to evaluate survival rate, and the Cox regression model was used to analyze multivariate analysis.

Results

In a total of 91 ASXL1+ AML, 86% had one or more co-mutations. The factors that had adverse impact on overall survival (OS) and event-free survival (EFS) are defined as high risk factors, including age ≥ 60 years, WBC count ≥ 50 × 10⁹/L, FLT3-ITD mutations, RUNX1 mutations, and absence of AML1-ETO fusion gene. ASXL1 mutations without any risk factor were classified as single-hit ASXL1+ AML; ASXL1 mutations accompanied with one of the risk factors was referred to as double-hit ASXL1+ AML; ASXL1 mutations with two or more of the risk factors were designated as triple-hit ASXL1+ AML. The combination of these risk factors had a negative influence on the prognosis of ASXL1+ AML. The median OS was not attained in single-hit ASXL1+ AML, 29.53 months in double-hit ASXL1+ AML, and 6.67 months in triple-hit ASXL1+ AML (P = 0.003). The median EFS was not attained in single-hit ASXL1+ AML, 29.53 months in double-hit ASXL1+ AML, and 5.47 months in triple-hit ASXL1+ AML (P = 0.002). Allogenic hematopoietic stem cell transplantation (allo-HSCT) improved the prognosis of double/triple-hit ASXL1+ AML patients.

Conclusions

Our study provided new insights into the mutational spectrum and prognostic factors of ASXL1+ AML patients. Our primary data suggest that the risk factors in ASXL1+ AML contribute to the poor outcome of these patients. The management of ASXL1+ AML patients should be based on the risk factors and allo-HSCT is highly recommended for consolidation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02233-y.

Clinical implication and prognostic significance of FLT3-ITD and ASXL1 mutations in Egyptian AML patients: A single-center study

BACKGROUND

Both Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) and Additional Sex Comb-like 1 (ASXL1) mutations are frequent and early genetic alteration events in acute myeloid leukemia (AML) patients. These genetic alterations may be associated with an unfavorable prognosis.

OBJECTIVE

Up to our knowledge, this is the first study performed to evaluate the clinical implication and prognostic significance of FLT3-ITD and ASXL1 mutations and their coexistence on the outcome of Egyptian AML patients.

METHODS

Our study included 83 patients with AML who were subjected to immunophenotyping and detection of FLT3-ITD and ASXL1 gene mutation by polymerase chain reaction (PCR) and real-time PCR, respectively.

RESULTS

FLT3-ITD and ASXL1 mutations were detected in 20.5% and 18.1% of AML patients respectively. Seven patients (8.4%) had co-expression of both genes' mutations. FLT3-ITD mutation was significantly higher in younger age, higher WBCs count and poor cytogenetic risk patients (P= 0.01, < 0.001 and 0.008 respectively). ASXL1 mutation was significantly higher in intermediate cytogenetic risk patients (P= 0.2). The mean period of survival and relapse-free survival (RFS) were significantly reduced in FLT3-ITD and ASXL1 mutations compared with their non-mutant types (P= 0.01 and 0.03 respectively). Both mutations were independent risk factors for overall survival (OS) and (RFS) in univariate and multivariate analysis in AML patients.

CONCLUSION

FLT3-ITD and ASXL1 gene mutations or their coexistence can predict a poor prognosis in AML patients.

3+7 Combined Chemotherapy for Acute Myeloid Leukemia: Is It Time to Say Goodbye?

PURPOSE OF REVIEW

With the recent approval of multiple new drugs for the treatment of acute myeloid leukemia (AML), the relevance of conventional treatment approaches, such as daunorubicin and cytarabine ("3+7") induction chemotherapy, has been challenged. We review the AML risk stratification, the efficacy of the newly approved drugs, and the role of "3+7".

RECENT FINDINGS

Treatment of AML is becoming more niched with specific subtypes more appropriately treated with gemtuzumab, midostaurin, and CPX-351. Although lower intensity therapies can yield high response rates, they are less efficient at preventing relapses. The only curative potential for poor-risk AML is still an allogeneic stem cell transplant. The number of AML subtypes where 3+7 alone is an appropriate therapeutic option is shrinking. However, it remains the backbone for combination therapy with newer agents in patients suitable for intensive chemotherapy.

Allogeneic hematopoietic stem cell transplantation could improve the survival of acute myeloid leukemia patients with ASXL1 mutations

Objective: To discover the function of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in ASXL1-mutated acute myeloid leukemia (AML) patients.Methods: We analyzed the prognostic value of ASXL1 mutations and explored the role of allo-HSCT in 581 AML patients.Results: According to the definition of intermediate- and adverse-risk AML groups in the European Leukemia Net (ELN), ASXL1-mutated patients had shorter OS and DFS than ASXL1-wild-type patients in the intermediate- and adverse-risk AML groups (3-year OS: 47.5% vs. 60.8%, P<0.001; 3-year DFS: 28.5% vs. 48.9%, P<0.001). Among the cytogenetically normal acute myeloid leukemia (CN-AML), differences were found in both OS (47.4% vs.65.2%, P<0.001) and DFS (21.0% vs. 52.1%, P<0.001) between ASXL1-mutated patients and ASXL1 wild-type patients.In the ASXL1-mutated AML cohort, the patients received allo-HSCT had longer 3-year OS (P=0.0005) and 3-year DFS (P<0.0001) than those who did not receive allo-HSCT. Multivariate analysis revealed that ASXL1 mutation was an independent prognostic factor for OS (HR 2.248, 95% CI 1.155-4.375, P=0.017), and allo-HSCT had a positive impact on OS (HR 7.568, 95% CI 3.597-15.92, P<0.001) and DFS (HR 2.611, 95% CI 1.688-4.039, P<0.001) in ASXL1-mutated patients.Conclusion: The results indicate that the presence of ASXL1 mutations is a factor predictive of poor prognosis in AML patients and allo-HSCT could improve the survival of AML patients with ASXL1 mutations.

Allogeneic stem cell transplantation for AML patients with RUNX1 mutation in first complete remission: a study on behalf of the acute leukemia working party of the EBMT

Acute myeloid leukemia with runt-related transcription factor 1 gene mutation (RUNX1+ AML) is associated with inferior response rates and outcome after conventional chemotherapy. We performed a retrospective, registry-based analysis to elucidate the prognostic value of RUNX1 mutation after allogeneic stem cell transplantation (alloSCT). All consecutive adults undergoing alloSCT for AML in first complete remission (CR1) between 2013 and 2019 with complete information on conventional cytogenetics and RUNX1 mutational status were included. Endpoints of interest were cumulative relapse incidence, non-relapse mortality, overall and leukemia-free survival (OS/LFS), and GvHD-free/relapse-free survival. A total of 674 patients (183 RUNX1+, 491 RUNX1−) were identified, with >85% presenting as de novo AML. Median follow-up was 16.4 (RUNX1+) and 21.9 (RUNX1−) months. Survival rates showed no difference between RUNX1+ and RUNX1− patients either in univariate or multivariate analysis (2-year OS: 67.7 vs. 66.1%, p = 0.7; 2-year LFS: 61.1 vs. 60.8%, p = 0.62). Multivariate analysis identified age, donor type and poor cytogenetics as risk factors for inferior outcome. Among patients with RUNX+ AML, older age, reduced intensity conditioning and minimal residual disease at alloSCT predicted inferior outcome. Our data provide evidence that the negative influence of RUNX1 mutations in patients with AML can be overcome by transplantation in CR1.

Prognostic impact of the ELN2017 risk classification in patients with AML receiving allogeneic transplantation

In 2017, an updated European LeukemiaNet (ELN) risk classification was published allocating patients with acute myeloid leukemia (AML) to 3 risk groups on the basis of certain cytogenetic and molecular aberrations. To date, studies of the prognostic significance of the ELN2017 risk classification in the context of an allogeneic hematopoietic stem cell transplantation (HSCT) are lacking. We performed risk stratification according to the ELN2017 classification in 234 patients with AML who underwent allogeneic HSCT as a consolidation therapy. In our cohort, the risk of 39.7% of the patients was classified as favorable, that of 12.8% as intermediate, and that of 47.4% as adverse. In the context of allogeneic HSCT, the assignment to the 3 ELN2017 risk groups retained its prognostic significance, with patients with favorable risk having the best prognosis and those with adverse risk having the worst one. Subgroup analyses showed that patients with a monosomal karyotype or TP53 mutation had considerably increased relapse rates, even in the adverse-risk group. When we analyzed the impact of digital droplet PCR-based measurable residual disease (MRD) before allogeneic HSCT, MRD+ patients had impaired prognoses, with cumulative incidence of relapse and overall survival comparable to those of patients classified as having an ELN2017 adverse genetic risk. This study is the first to demonstrate that the ELN2017 classification distinguishes the 3 risk groups with significantly distinct prognoses, even after allogeneic HSCT, and emphasizes the dismal prognosis of patients with AML with TP53 mutations, monosomal karyotype, or MRD positivity after allogeneic HSCT.

The Impact of Epigenetic Modifications in Myeloid Malignancies

Myeloid malignancy is a broad term encapsulating myeloproliferative neoplasms (MPN), myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). Initial studies into genomic profiles of these diseases have shown 2000 somatic mutations prevalent across the spectrum of myeloid blood disorders. Epigenetic mutations are emerging as critical components of disease progression, with mutations in genes controlling chromatin regulation and methylation/acetylation status. Genes such as DNA methyltransferase 3A (DNMT3A), ten eleven translocation methylcytosine dioxygenase 2 (TET2), additional sex combs-like 1 (ASXL1), enhancer of zeste homolog 2 (EZH2) and isocitrate dehydrogenase 1/2 (IDH1/2) show functional impact in disease pathogenesis. In this review we discuss how current knowledge relating to disease progression, mutational profile and therapeutic potential is progressing and increasing understanding of myeloid malignancies.

Advances in therapeutic options for newly diagnosed, high-risk AML patients

Acute myeloid leukemia (AML) is an aggressive malignancy characterized by clonal proliferation of neoplastic immature precursor cells. AML impacts older adults and has a poor prognosis. Despite recent advances in treatment, AML is complex, with both genetic and epigenetic aberrations in the malignant clone and elaborate interactions with its microenvironment. We are now able to stratify patients on the basis of specific clinical and molecular features in order to optimize individual treatment strategies. However, our understanding of the complex nature of these molecular abnormalities continues to expand the defining characteristics of high-risk mutations. In this review, we focus on genetic and microenvironmental factors in adverse risk AML that play critical roles in leukemogenesis, including those not described in an European LeukemiaNet adverse risk group, and describe therapies that are currently in the clinical arena, either approved or under development.

Clonal haematopoiesis of indeterminate potential: intersections between inflammation, vascular disease and heart failure

Ageing is a major risk factor for the development of cardiovascular disease (CVD) and cancer. Whilst the cumulative effect of exposure to conventional cardiovascular risk factors is important, recent evidence highlights clonal haematopoiesis of indeterminant potential (CHIP) as a further key risk factor. CHIP reflects the accumulation of somatic, potentially pro-leukaemic gene mutations within haematopoietic stem cells over time. The most common mutations associated with CHIP and CVD occur in genes that also play central roles in the regulation of inflammation. While CHIP carriers have a low risk of haematological malignant transformation (<1% per year), their relative risk of mortality is increased by 40% and this reflects an excess of cardiovascular events. Evidence linking CHIP, inflammation and atherosclerotic disease has recently become better defined. However, there is a paucity of information about the role of CHIP in the development and progression of heart failure, particularly heart failure with preserved ejection fraction (HFpEF). While systemic inflammation plays a role in the pathophysiology of both heart failure with reduced and preserved ejection fraction (EF), it may be of greater relevance in the pathophysiology of HFpEF, which is also strongly associated with ageing. This review describes CHIP and its pathogenetic links with ageing, inflammation and CVD, while providing insight into its putative role in HFpEF.

The ASXL1-G643W variant accelerates the development of CEBPA mutant acute myeloid leukemia

ASXL1 is one of the most commonly mutated genes in myeloid malignancies, including myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). In order to further our understanding of the role of ASXL1 lesions in malignant hematopoiesis, we generated a novel knockin mouse model carrying the most frequent ASXL1 mutation identified in MDS patients, ASXL1 p.G643WfsX12. Mutant mice neither displayed any major hematopoietic defects nor developed any apparent hematological disease. In AML patients, ASXL1 mutations co-occur with mutations in CEBPA and we therefore generated compound Cebpa and Asxl1 mutated mice. Using a transplantation model, we found that the mutated Asxl1 allele significantly accelerated disease development in a CEBPA mutant context. Importantly, we demonstrated that, similar to the human setting, Asxl1 mutated mice responded poorly to chemotherapy. This model therefore constitutes an excellent experimental system for further studies into the clinically important question of chemotherapy resistance mediated by mutant ASXL1.

Diagnosis of rare subtypes of acute myeloid leukaemia and related neoplasms

The diagnosis of acute myeloid leukaemia and related neoplasms in adults is challenging as this requires the integration of clinical findings, morphology, immunophenotype, cytogenetics, and molecular genetic findings. Lack of familiarity with rare subtypes of acute leukaemia hinders the diagnosis. In this review, we will describe diagnostic findings of several rare acute myeloid leukaemias and related neoplasms that primarily occur in adults including information on presentation, morphology, immunophenotype, genetics, differential diagnosis, and prognosis. Leukaemias discussed include blastic plasmacytoid dendritic cell neoplasm, acute myeloid leukaemia with t(6;9) (p23;q34.1); DEK-NUP214, acute myeloid leukaemia with inv(3)(q21.3q26.2) or t(3;3)(q21.3;q26.2); GATA2, MECOM, acute myeloid leukaemia with BCR-ABL1, acute leukaemias of ambiguous lineage, acute myeloid leukaemia with mutated RUNX1, pure erythroid leukaemia, acute panmyelosis with myelofibrosis, and acute basophilic leukaemia. Case studies with morphological features of the nine subtypes of acute myeloid leukaemia and related neoplasms have been included, and additional evidence available since publication of the 2016 World Health Organization Classification has been added to each subtype.

Genomic characteristics and prognostic significance of co-mutated ASXL1/SRSF2 acute myeloid leukemia

The ASXL1 and SRSF2 mutations in AML are frequently found in patients with preexisting myeloid malignancies and are individually associated with poor outcomes. In this multi-institutional retrospective analysis, we assessed the genetic features and clinical outcomes of 43 patients with ASXL1^mut SRSF2^mut AML and compared outcomes to patients with either ASXL1 (n = 57) or SRSF2 (n = 70) mutations. Twenty-six (60%) had secondary-AML (s-AML). Variant allele fractions suggested that SRSF2 mutations preceded ASXL1 mutational events. Median overall survival (OS) was 7.0 months (95% CI:3.8,15.3) and was significantly longer in patients with de novo vs s-AML (15.3 vs 6.4 months, respectively; P = .04 on adjusted analysis). Compared to ASXL1^mut SRSF2^wt and ASXL1^wt SRSF2^mut , co-mutated patients had a 1.4 and 1.6 times increase in the probability of death, respectively (P = .049), with a trend towards inferior OS (median OS = 7.0 vs 11.5 vs 10.9 months, respectively; P = .10). Multivariable analysis suggests this difference in OS is attributable to the high proportion of s-AML patients in the co-mutated cohort (60% vs 32% and 23%, respectively). Although this study is limited by the retrospective data collection and the relatively small sample size, these data suggest that ASXL1^mut SRSF2^mut AML is a distinct subgroup of AML frequently associated with s-AML and differs from ASXL1^mut SRSF2^wt /ASXL1^wt SRSF2^mut with respect to etiology and leukemogenesis.

ELN 2017 Genetic Risk Stratification Predicts Survival of Acute Myeloid Leukemia Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation

European LeukemiaNet (ELN) 2017 risk stratification by genetics is prognostic of outcomes in patients with acute myeloid leukemia (AML). However, the prognostic impact of the 2017 ELN genetic risk stratification after allogeneic hematopoietic cell transplantation (alloHCT) is not well established. We examined the effect of 2017 ELN genetic risk stratification on alloHCT outcomes of AML. We included 500 adult (≥18 years) AML patients in first (n = 370) or second (n = 130) complete remission receiving alloHCT from 2005 to 2016. Patients were classified into favorable (12%), intermediate (57%), and adverse (32%) 2017 ELN risk groups. The Cox proportional hazard model was used to conduct the multivariable analyses of leukemia-free survival (LFS) and overall survival (OS). Relapse and nonrelapse mortality were analyzed by the Fine-Gray regression model. OS at 2 years was 72% in the favorable versus 60% in the intermediate versus 45% in the adverse risk groups (P < .001). In multivariable analyses, the 2017 ELN classifier was an independent predictor of OS after alloHCT with significantly higher overall mortality in the intermediate (hazard ratio [HR] = 1.68, 95% confidence interval [CI], 1.06-2.68; P = .03) and adverse (HR = 2.50, 95% CI, 1.54-4.06; P < .001) risk groups compared to the favorable risk group. Similarly, LFS was worse in the intermediate (HR = 1.63, 95%, CI 1.06-2.53; P = .03) and adverse (HR 2.23, 95% CI, 1.41-3.54; P < .001) risk groups while relapse was higher in the adverse risk group (HR = 2.36, 95% CI, 1.28-4.35; P = .006) as compared to the favorable risk group. These data highlight the prognostic impact of the 2017 ELN genetic risk stratification on the survival of AML patients after alloHCT. Patients in the adverse risk group had the highest risk of relapse and worst survival. Thus the 2017 ELN prognostic system can help identify AML patients who may benefit from clinical trials offering relapse mitigation strategies to improve transplant outcomes.

[RUNX1 gene mutations are associated with adverse prognosis of patients with acute myeloidleukemia]

OBJECTIVE

To explore the rate and distribution of Runt- related transcription factor 1 (RUNX1) gene mutations in patients with acute myeloid leukemia (AML) and the correlation of these mutations with the clinical characteristics and survival outcomes of the patients.

METHODS

The genomic DNA extracted from the bone marrow of 158 patients with newly diagnosed AML for PCR amplification of RUNX1 gene and sequence analysis to identify the mutations. The mutations of ASXL1, DNMT3A, TET2, FLT3, CEBPA, NPM1, IDH2, NRAS and c-KIT genes were also examined to analyze their association with RUNX1 gene mutations.

RESULTS

Among the 158 AML patients, 19 (12.0%) were found to have RUNX1 mutations in A166G (9 cases), A142T (6 cases) and A162L (4 cases). RUNX1 mutations were more frequent in elderly patients (P < 0.01) and in cases of AML subtypes M4 and M5, and were associated with more frequent CD36 and CD7 expression as compared with the wild type. RUNX1 mutations were more likely to occur in patients with normal karyotype or karyotypes associated with moderate prognostic risks, but the difference was not significant (P > 0.05). The patients with RUNX1 mutations had significantly lower complete remission (CR) rate and overall survival (OS) rate than those without the mutations (P < 0.05). RUNX1 mutations were not associated with gender, white blood cell count upon diagnosis, hemoglobin level, platelet count, bone marrow blast cell ratio or lactate dehydrogenase level (P > 0.05).

CONCLUSIONS

RUNX1 gene mutations are associated with an adverse prognosis of patients with AML.

Clinical features and prognosis of normal karyotype acute myeloid leukemia pediatric patients with WT1 mutations: an analysis based on TCGA database

Objectives: To explore the clinical features and prognosis of normal karyotype acute myeloid leukemia (NK-AML) pediatric patients with WT1 mutations.Methods: The clinical data and prognostic information of 220 NK-AML pediatric patients were selected from target-AML project of The Cancer Genome Atlas (TCGA) database. Survival analyses were performed for NK-AML pediatric patients with different combinations of mutations.Results: We found that 28(12.7%) NK-AML patients harbored WT1 mutations. The positive rate of FLT3-ITD in the WT1-mutated group was higher than that in the WT1 wild-type group (P = 0.002). In contrast, WT1 mutation and NPM1 mutation were mutually exclusive (P = 0.013). Furthermore, the WT1-mutated group suffered lower rates of complete remission (CR) (P < 0.001 and P < 0.001, respectively) but higher rates of minimal residual disease (MRD) (P = 0.003 and P = 0.021, respectively) after both one and two courses of induction chemotherapy. Patients with WT1 mutations had significantly worse overall survival (OS) and event-free survival (EFS) in both univariate (P < 0.001 and P = 0.007, respectively) and multivariate survival analyses (P < 0.001 and P < 0.001, respectively). The stratification analysis showed that for FLT3-ITD positive patients, WT1 mutations predicted shorter OS (P = 0.003) and EFS (P < 0.001).Conclusion: WT1 mutations conferred an independent poor prognosis for NK-AML pediatric patients.

Genomic landscape in acute myeloid leukemia and its implications in risk classification and targeted therapies

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy in terms of clinical features, underlying pathogenesis and treatment outcomes. Recent advances in genomic techniques have unraveled the molecular complexity of AML leukemogenesis, which in turn have led to refinement of risk stratification and personalized therapeutic strategies for patients with AML. Incorporation of prognostic and druggable genetic biomarkers into clinical practice to guide patient-specific treatment is going to be the mainstay in AML therapeutics. Since 2017 there has been an explosion of novel treatment options to tailor personalized therapy for AML patients. In the past 3 years, the U.S. Food and Drug Administration approved a total of eight drugs for the treatment of AML; most specifically target certain gene mutations, biological pathways, or surface antigen. These novel agents are especially beneficial for older patients or those with comorbidities, in whom the treatment choice is limited and the clinical outcome is very poor. How to balance efficacy and toxicity to further improve patient outcome is clinically relevant. In this review article, we give an overview of the most relevant genetic markers in AML with special focus on the therapeutic implications of these aberrations.

A comprehensive review of genetic alterations and molecular targeted therapies for the implementation of personalized medicine in acute myeloid leukemia

Acute myeloid leukemia (AML) is an extremely heterogeneous disease defined by the clonal growth of myeloblasts/promyelocytes not only in the bone marrow but also in peripheral blood and/or tissues. Gene mutations and chromosomal abnormalities are usually associated with aberrant proliferation and/or block in the normal differentiation of hematopoietic cells. So far, the combination of cytogenetic profiling and molecular and gene mutation analyses remains an essential tool for the classification, diagnosis, prognosis, and treatment for AML. This review gives an overview on how the development of novel innovative technologies has allowed us not only to detect the genetic alterations as early as possible but also to understand the molecular pathogenesis of AML to develop novel targeted therapies. We also discuss the remarkable advances made during the last decade to understand the AML genome both at primary and relapse diseases and how genetic alterations might influence the distinct biological groups as well as the clonal evolution of disease during the diagnosis and relapse. Also, the review focuses on how the persistence of epigenetic gene mutations during morphological remission is associated with relapse. It is suggested that along with the prognostic and therapeutic mutations, the novel molecular targeted therapies either approved by FDA or those under clinical trials including CART-cell therapy would be of immense importance in the effective management of AML.

Clinical implications of recurrent gene mutations in acute myeloid leukemia

Acute myeloid leukemia (AML) is a genetically heterogeneous clonal malignancy characterized by recurrent gene mutations. Genomic heterogeneity, patients’ individual variability, and recurrent gene mutations are the major obstacles among many factors that impact treatment efficacy of the AML patients. With the application of cost- and time-effective next-generation sequencing (NGS) technologies, an enormous diversity of genetic mutations has been identified. The recurrent gene mutations and their important roles in acute myeloid leukemia (AML) pathogenesis have been studied extensively. In this review, we summarize the recent development on the gene mutation in patients with AML.

ASXL1 mutation as a surrogate marker in acute myeloid leukemia with myelodysplasia-related changes and normal karyotype

Acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) are poor outcome leukemias. Its diagnosis is based on clinical, cytogenetic, and cytomorphologic criteria, last criterion being sometimes difficult to assess. A high frequency of ASXL1 mutations have been described in this leukemia. We sequenced ASXL1 gene mutations in 61 patients with AML-MRC and 46 controls with acute myeloid leukemia without other specifications (AML-NOS) to identify clinical, cytomorphologic, and cytogenetic characteristics associated with ASXL1 mutational status. Mutated ASXL1 (ASXL1+) was observed in 31% of patients with AML-MRC compared to 4.3% in AML-NOS. Its presence in AML-MRC was associated with older age, a previous history of myelodysplastic syndrome (MDS) or myelodysplastic/myeloproliferative neoplasms (MDS/MPN), leukocytosis, presence of micromegakaryocytes in bone marrow, lower number of blasts in bone marrow, myelomonocytic/monocytic morphological features and normal karyotype. ASXL1 mutation was not observed in patients with myelodysplastic syndrome-related cytogenetic abnormalities or TP53 mutations. Differences in terms of overall survival were found only in AML-MRC patients without prior MDS or MDS/MPN and with intermediate-risk karyotype, having ASXL1+ patients a worst outcome than ASXL1-. We conclude that the ASXL1 mutation frequency is high in AML-MRC patients being its presence associated with specific characteristics including morphological signs of dysplasia. This association raises the possible role of ASXL1 as a surrogate marker in AML-MRC, which could facilitate the diagnosis of patients within this group when the karyotype is normal, and especially when the assessment of multilineage dysplasia morphologically is difficult. This mutation could be used as a worst outcome marker in de novo AML-MRC with intermediate-risk karyotype.

Landscape of Tumor Suppressor Mutations in Acute Myeloid Leukemia

Acute myeloid leukemia is mainly characterized by a complex and dynamic genomic instability. Next-generation sequencing has significantly improved the ability of diagnostic research to molecularly characterize and stratify patients. This detailed outcome allowed the discovery of new therapeutic targets and predictive biomarkers, which led to develop novel compounds (e.g., IDH 1 and 2 inhibitors), nowadays commonly used for the treatment of adult relapsed or refractory AML. In this review we summarize the most relevant mutations affecting tumor suppressor genes that contribute to the onset and progression of AML pathology. Epigenetic modifications (TET2, IDH1 and IDH2, DNMT3A, ASXL1, WT1, EZH2), DNA repair dysregulation (TP53, NPM1), cell cycle inhibition and deficiency in differentiation (NPM1, CEBPA, TP53 and GATA2) as a consequence of somatic mutations come out as key elements in acute myeloid leukemia and may contribute to relapse and resistance to therapies. Moreover, spliceosomal machinery mutations identified in the last years, even if in a small cohort of acute myeloid leukemia patients, suggested a new opportunity to exploit therapeutically. Targeting these cellular markers will be the main challenge in the near future in an attempt to eradicate leukemia stem cells.

Epigenetic Therapies for Acute Myeloid Leukemia and Their Immune-Related Effects

Over the past decades, our molecular understanding of acute myeloid leukemia (AML) pathogenesis dramatically increased, thanks also to the advent of next-generation sequencing (NGS) technologies. Many of these findings, however, have not yet translated into new prognostic markers or rationales for treatments. We now know that AML is a highly heterogeneous disease characterized by a very low mutational burden. Interestingly, the few mutations identified mainly reside in epigenetic regulators, which shape and define leukemic cell identity. In the light of these discoveries and given the increasing number of drugs targeting epigenetic regulators in clinical development and testing, great interest is emerging for the use of small molecules targeting leukemia epigenome. Together with their effects on leukemia cell-intrinsic properties, such as proliferation and survival, epigenetic drugs may affect the way leukemic cells communicate with the surrounding components of the tumor and immune microenvironment. Here, we review current knowledge on alterations in the AML epigenetic landscape and discuss the promises of epigenetic therapies for AML treatment. Finally, we summarize emerging molecular studies elucidating how epigenetic rewiring in cancer cells may as well exert immune-modulatory functions, boost the immune system, and potentially contribute to better patient outcomes.

Randomized phase-II trial evaluating induction therapy with idarubicin and etoposide plus sequential or concurrent azacitidine and maintenance therapy with azacitidine

The aim of this randomized phase-II study was to evaluate the effect of substituting cytarabine by azacitidine in intensive induction therapy of patients with acute myeloid leukemia (AML). Patients were randomized to four induction schedules for two cycles: STANDARD (idarubicin, cytarabine, etoposide); and azacitidine given prior (PRIOR), concurrently (CONCURRENT), or after (AFTER) therapy with idarubicin and etoposide. Consolidation therapy consisted of allogeneic hematopoietic-cell transplantation or three courses of high-dose cytarabine followed by 2-year maintenance therapy with azacitidine in the azacitidine-arms. AML with CBFB-MYH11, RUNX1-RUNX1T1, mutated NPM1, and FLT3-ITD were excluded and accrued to genotype-specific trials. The primary end point was response to induction therapy. The statistical design was based on an optimal two-stage design applied for each arm separately. During the first stage, 104 patients (median age 62.6, range 18-82 years) were randomized; the study arms PRIOR and CONCURRENT were terminated early due to inefficacy. After randomization of 268 patients, all azacitidine-containing arms showed inferior response rates compared to STANDARD. Event-free and overall survival were significantly inferior in the azacitidine-containing arms compared to the standard arm (p < 0.001 and p = 0.03, respectively). The data from this trial do not support the substitution of cytarabine by azacitidine in intensive induction therapy.

The role of ASXL1 in hematopoiesis and myeloid malignancies

Recent high-throughput genome-wide sequencing studies have identified recurrent somatic mutations in myeloid neoplasms. An epigenetic regulator, Additional sex combs-like 1 (ASXL1), is one of the most frequently mutated genes in all subtypes of myeloid malignancies. ASXL1 mutations are also frequently detected in clonal hematopoiesis, which is associated with an increased risk of mortality. Therefore, it is important to understand how ASXL1 mutations contribute to clonal expansion and myeloid transformation in hematopoietic cells. Studies using ASXL1-depleted human hematopoietic cells and Asxl1 knockout mice have shown that deletion of wild-type ASXL1 protein leads to impaired hematopoiesis and accelerates myeloid malignancies via loss of interaction with polycomb repressive complex 2 proteins. On the other hand, ASXL1 mutations in myeloid neoplasms typically occur near the last exon and result in the expression of C-terminally truncated mutant ASXL1 protein. Biological studies and biochemical analyses of this variant have shed light on its dominant-negative and gain-of-function features in myeloid transformation via a variety of epigenetic changes. Based on these results, it would be possible to establish novel promising therapeutic strategies for myeloid malignancies harboring ASXL1 mutations by blocking interactions between ASXL1 and associating epigenetic regulators. Here, we summarize the clinical implications of ASXL1 mutations, the role of wild-type ASXL1 in normal hematopoiesis, and oncogenic functions of mutant ASXL1 in myeloid neoplasms.

Clonal evolution patterns in acute myeloid leukemia with NPM1 mutation

Mutations in the nucleophosmin 1 (NPM1) gene are considered founder mutations in the pathogenesis of acute myeloid leukemia (AML). To characterize the genetic composition of NPM1 mutated (NPM1^mut) AML, we assess mutation status of five recurrently mutated oncogenes in 129 paired NPM1^mut samples obtained at diagnosis and relapse. We find a substantial shift in the genetic pattern from diagnosis to relapse including NPM1^mut loss (n = 11). To better understand these NPM1^mut loss cases, we perform whole exome sequencing (WES) and RNA-Seq. At the time of relapse, NPM1^mut loss patients (pts) feature distinct mutational patterns that share almost no somatic mutation with the corresponding diagnosis sample and impact different signaling pathways. In contrast, profiles of pts with persistent NPM1^mut are reflected by a high overlap of mutations between diagnosis and relapse. Our findings confirm that relapse often originates from persistent leukemic clones, though NPM1^mut loss cases suggest a second "de novo" or treatment-associated AML (tAML) as alternative cause of relapse.

Myeloid malignancies with isolated 7q deletion can be further characterized by their accompanying molecular mutations

Deletions in the long arm of chromosome 7 (del(7q)) are recurrent cytogenetic aberrations in myeloid neoplasms. They occur either isolated or as part of a complex karyotype and are associated with unfavorable prognosis in certain disease entities. We performed detailed cytogenetic analysis, molecular analysis, and array comparative genomic hybridization in a cohort of 81 patients with a variety of myeloid malignancies and del(7q) as sole chromosomal alteration. In 70% (57/81) of patients, we identified a commonly deleted region (size: 18 Mb) involving the genomic region 101 912.442 (7q22.1)-119 608.824 (7q31.31). Furthermore, in 80 patients, we analyzed 17 genes commonly mutated in myeloid neoplasms and identified high mutation frequencies in ASXL1 34% (27/80), TET2 33% (26/80), RUNX1 25% (20/80), DNMT3A 25% (20/80), while TP53 was rarely affected (5%, 4/80). ASXL1 and TET2 showed similar mutation frequencies across all analyzed entities while RUNX1, CBL, and JAK2 were specifically mutated in patients with acute myeloid leukemia (AML), chronic myelomonocytic leukemia, and myeloproliferative neoplasms, respectively. We detected a significantly higher frequency of RUNX1 (42% vs 13%, P = .0001) and ASXL1 (32% vs 14%, P = .008) mutations in AML patients with del(7q) compared to other AML patients in the Medical Research Council unfavorable risk group (n = 464), indicating a cooperative leukemogenic potential. Our data provide further insight into the pathomechanism of this cytogenetic subgroup.

The prognostic impact of tet oncogene family member 2 mutations in patients with acute myeloid leukemia: a systematic-review and meta-analysis

Background

The impact of Tet oncogene family member 2 (TET2) mutations on the prognosis of acute myeloid leukemia (AML) is still controversial. A meta analysis is needed in order to assess the prognostic significance of TET2 mutation in AML.

Methods

Five databases including PubMed, Cochrane, EMBase, China National Knowledge Internet (CNKI) and Wanfang database were retrieved to search studies that investigated the correlation between TET2 mutations and outcomes of AML patients. Pooled hazard ratios (HRs) and odds ratios (ORs) were used to assess the effects of TET2 mutations.

Results

Sixteen studies were included. TET2 mutation was an unfavorable prognostic factor for overall survival (OS: HR = 1.386; P < 0.001) and event-free survival (EFS: HR = 1.594; P = 0.002) in patients with AML. For patients under 65 years of age, TET2 mutation predicted an inferior OS (HR = 1.310, P = 0.051) and EFS (HR = 1.429, P = 0.027). For patients with intermediate-risk cytogenetics (IR-AML), mutant TET2 had a significant association with adverse OS (HR = 0.474; P < 0.001). For patients with normal cytogenetics (CN-AML), mutant TET2 also conferred adverse OS (HR = 1.425; P < 0.001) and EFS (HR = 1.450, P < 0.001). Further, among patients with CN-AML, mutant TET2 was associated with inferior OS (HR = 2.034, P < 0.001) and EFS (HR = 2.140, P < 0.001) in the ELN favorable-risk subgroup and an inferior EFS (HR = 1.487; P < 0.001) in the ELN intermediate-Isubgroup. With respect to treatment outcome, TET2 mutation predicted a significantly lower rate of complete remission (CR) in cases with ELN favorable-risk cytogenetics (OR = 0.460, P = 0.011).

Conclusions

TET2 mutation had adverse impacts on survival and treatment response in AML patients and will contribute to risk-stratification, prognosis prediction and therapy guidance.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5602-8) contains supplementary material, which is available to authorized users.

Prognostic significance of PAK family kinases in acute myeloid leukemia

Acute myeloid leukemia (AML) is a clonal and heterogeneous disease characterized by a myriad of genetic defects. Genetic abnormalities are powerful prognostic factors. P21-activated kinases (PAKs) are a kind of serine/threonine protein kinases, which is regulator of plenty of oncogenic signaling pathways. The clinical and prognostic value of PAKs in AML is unclear. A total of 155 AML patients with PAK expression data from The Cancer Genome Atlas database were enrolled in this study. Eighty-four patients underwent chemotherapy only, 71 also underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the chemotherapy-only group, high PAK3 and PAK7 expression were both bound up with poor EFS and OS (all P < 0.05). However, high PAK2 expressers had better EFS and OS (all P < 0.05). Multivariate analysis demonstrated that high PAK7 expression was an adverse independent prognostic factor in patients who received chemotherapy only. PAKs have no influence in EFS and OS in patients who underwent allo-HSCT. In conclusion, high PAK2 expression is a favorable prognostic factor, as to the high expression of PAK3 and PAK7, they are poor prognostic factors, and PAK7 has better prognostic value, but their prognostic effects can be offset by allo-HSCT.

The 2016 WHO classification of acute myeloid leukemia: What the practicing clinician needs to know

In 2016 a revision of the World Health Organization (WHO) classification of acute myeloid leukemia (AML) was introduced that included changes to several disease categories. The WHO approach results in disease categories that are defined by a combination of clinical, morphologic, immunophenotypic, and genetic features in an attempt to define clinically relevant, biologic entities. This review summarizes the WHO approach as well as the priority of specific features for disease classification. Changes to specific categories, including AML with myelodysplasia-related changes, AML with mutated NPM1, AML with biallelic mutations of CEBPA and erythroleukemia are summarized. The importance of additional gene mutations as well as germline predisposition in AML is also reviewed.

Acute Myeloid Leukemia: The Good, the Bad, and the Ugly

Acute myeloid leukemia (AML) was initially subdivided according to morphology (the French-American-British system), which proved helpful in pathologic categorization. Subsequently, clinical and genomic factors were found to correlate with response to chemotherapy and with overall survival. These included a history of antecedent hematologic disease, a history of chemotherapy or radiation therapy, the presence of various recurrent cytogenetic abnormalities, and, more recently, the presence of specific point mutations. This article reviews the biology and responses of one AML subgroup with consistent response and good outcomes following chemotherapy (core-binding factor leukemia), and two subgroups with persistently bad, and even ugly, outcomes (secondary AML and TP53-mutated AML).