Next-generation sequencing reveals gene mutations landscape and clonal evolution in patients with acute myeloid leukemia

Prevalence of RUNX1 gene alterations in de novo adult acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a complicated disease with uncontrolled hematopoietic precursor proliferation induced by various genetic alterations. Runt-related transcription factor-1 (RUNX1) is commonly disrupted by chromosomal translocations in hematological malignancies.

AIM

To characterize RUNX1 gene rearrangements and copy number variations in newly diagnosed adult AML patients, with an emphasis on the impact of clinical and laboratory features on the outcome.

METHODS

Fluorescence in situ hybridization was used to test RUNX1 gene alterations in 77 newly diagnosed adult AML cases. NPM1, FLT3/ITD, FLT3/TKD, and KIT mutations were tested by PCR. Prognostic clinical and laboratory findings were studied in relation to RUNX1 alterations.

RESULTS

RUNX1 abnormalities were detected by fluorescence in situ hybridization in 41.6% of patients: 20.8% had translocations, 22.1% had amplification, and 5.2% had deletion. Translocations prevailed in AML-M2 (P = 0.019) with a positive expression of myeloperoxidase (P = 0.031), whereas deletions dominated in M4 and M5 subtypes (P = 0.008) with a positive association with CD64 expression (P = 0.05). The modal chromosomal number was higher in cases having amplifications (P = 0.007) and lower in those with deletions (P = 0.008). RUNX1 abnormalities were associated with complex karyotypes (P < 0.001) and were mutually exclusive of NPM1 mutations. After 44 months of follow-up, RUNX1 abnormalities affected neither patients' response to treatment nor overall survival.

CONCLUSION

RUNX1 abnormalities were mutually exclusive of NPM1 mutations. RUNX1 abnormalities affected neither patients' response to treatment nor overall survival.

Effect of Age, Sex and Season on Acute Myeloid Leukemia Clinical Characteristics: A Retrospective Study

Background

Acute myeloid leukemia (AML) is a lethal malignancy of the bone marrow, characterized by rapid proliferation of immature myeloid cells, leading to insufficient hematopoiesis and immune activities. It is well known that AML is closely associated with various molecular and cytogenetic abnormalities. In addition, the long-standing view that non-genetic factors, including age, sex and season, are also associated with the occurrence and development of AML. However, effects of these factors on AML clinical characteristics remain incompletely understood. During clinical practice, we perceived an imbalance distribution of clinical characteristics (including FAB classification, gene mutations, lymphocyte-associated cytokine levels and lymphocyte-subset proportions) in different age, sex and season groups. In order to elucidate the correlations between these factors, we performed a comprehensive data collection and analysis of AML patients in our hospital from 2013 to 2023.

Methods

Totally, 2798 newly diagnosed AML patients and 220 relapsed AML patients who were admitted to our hospital from January 1, 2013 to December 31, 2023 were included for analysis. Chi-square test was conducted to analyze the correlation between categorical variables. T-tests and one-way ANOVA were employed to compare mean values across two and multiple groups respectively. Mann-Whitney U-tests and Kruskal-Wallis H-tests were employed to compare mean values across two and multiple groups respectively, when data did not show normal distribution. Logistic regression was used to analyze the correlation between dependent and independent variables. Log rank test was applied for survival analysis. Waterfall diagram and chord diagram of mutated genes were created using R4.3.3 and RStudio tools.

Results

Overall, the distribution of age, sex and season in AML patients were unbalanced. The relationships among various mutated genes had two sides, co-existence or mutual exclusivity. Additionally, the FAB classification and gene mutation status varied significantly across the subgroups. The levels of cytokines and lymphocyte subsets altered significantly in AML patients, and were associated with prognosis and gene mutations.

Conclusion

Age, sex and season have shown partial correlations with AML clinical characteristics, including FAB classification, gene mutations status, lymphocyte-associated cytokine levels and lymphocyte subset proportions. We hope these findings can contribute to a deeper understanding of AML.

Recent Developments and Evolving Therapeutic Strategies in KMT2A-Rearranged Acute Leukemia

BACKGROUND

Rearrangements of the histone-lysine-N-methyltransferase (KMT2A), previously referred to as mixed-lineage leukemia (MLL), are among the most common chromosomal abnormalities in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), involving numerous different fusion partners. KMT2A-rearranged (KMT2A-r) leukemia is characterized by a rapid onset, aggressive progression, and significantly worse prognosis compared to non-KMT2A-r leukemias. Even with contemporary chemotherapeutic treatments and hematopoietic stem cell transplantations (HSCT), patients with KMT2A-r leukemia typically experience poor outcomes and limited responses to these therapies.

OBJECTIVES

This review aims to consolidate recent studies on the general gene characteristics and associated mechanisms of KMT2A-r acute leukemia, as well as the cytogenetics, immunophenotype, clinical presentation, and risk stratification of both KMT2A-r-AML and KMT2A-r-ALL. Particularly, the treatment targets in KMT2A-r acute leukemia are examined.

METHODS

A comprehensive review was carried out by systematically synthesizing existing literature on PubMed, using the combination of the keywords 'KMT2A-rearranged acute leukemia', 'lymphoblastic leukemia', 'myeloid leukemia', and 'therapy'. The available studies were screened for selection based on quality and relevance.

CONCLUSIONS

Studies indicate that KMT2A rearrangements are present in over 70% of infant leukemia cases, approximately 10% of adult AML cases, and numerous instances of secondary acute leukemias, making it a disease of critical concern to clinicians and researchers alike. The future of KMT2A-r acute leukemia research is characterized by an expanding knowledge of the disease's biology, with an emphasis on personalized therapies, immunotherapies, genomic advancements, and innovative therapeutic combinations. The overarching aim is to enhance patient outcomes, lessen the disease burden, and elevate the quality of life for those affected. Ongoing research and clinical trials in this area continue to offer promising opportunities for refining treatment strategies and improving patient prognosis.

Clinical prognostic value of different NPM1 mutations in acute myeloid leukemia patients

BACKGROUND

Acute myeloid leukemia (AML) patients with various nucleophosmin 1 (NPM1) mutations are controversial in the prognosis. This study aimed to investigate the prognosis of patients according to types of NPM1 mutations (NPM1mut).

METHODS

Bone marrow samples of 528 patients newly diagnosed with AML, were collected for morphology, immunology, cytogenetics, and molecular biology examinations. Gene mutations were detected by next-generation sequencing (NGS) technology.

RESULTS

About 25.2% of cases exhibited NPM1mut. 83.5% of cases were type A, while type B and D were respectively account for 2.3% and 3.0%. Furthermore, 15 cases of rare types were identified, of which 2 cases have not been reported. Clinical characteristics were similar between patients with A-type NPM1 mutations (NPM1A - type mut) and non-A-type NPM1 mutations (NPM1non - A-type mut). Event-free survival (EFS) was significantly different between patients with low NPM1non - A-type mut variant allele frequency (VAF) and low NPM1A - type mut VAF (median EFS = 3.9 vs. 8.5 months, P = 0.020). The median overall survival (OS) of the NPM1non - A-type mutFLT3-ITDmut group, the NPM1A - type mutFLT3-ITDmut group, the NPM1non - A-type mutFLT3-ITDwt group, and the NPM1A - type mutFLT3-ITDwt group were 3.9, 10.7, 17.3 and 18.8 months, while the median EFS of the corresponding groups was 1.4, 5.0, 7.6 and 9.2 months (P < 0.0001 and P = 0.004, respectively).

CONCLUSIONS

No significant difference was observed in OS and EFS between patients with NPM1A - type mut and NPM1non - A-type mut. However, types of NPM1 mutations and the status of FLT3-ITD mutations may jointly have an impact on the prognosis of AML patients.

Pediatric acute myeloid leukemia: Insight into genetic landscape and novel targeted approaches

Acute myeloid leukemia (AML) is a very heterogeneous hematological malignancy that accounts for approximately 20% of all pediatric leukemia cases. The outcome of pediatric AML has improved over the last decades, with overall survival rates reaching up to 70%. Still, AML is among the leading types of pediatric cancers by its high mortality rate. Modulation of standard therapy, like chemotherapy intensification, hematopoietic stem cell transplantation and optimized supportive care, could only get this far, but for the significant improvement of the outcome in pediatric AML, development of novel targeted therapy approaches is necessary. In recent years the advances in genomic techniques have greatly expanded our knowledge of the AML biology, revealing molecular landscape and complexity of the disease, which in turn have led to the identification of novel therapeutic targets. This review provides a brief overview of the genetic landscape of pediatric AML, and how it's used for precise molecular characterization and risk stratification of the patients, and also for the development of effective targeted therapy. Furthermore, this review presents recent advances in molecular targeted therapy and immunotherapy with an emphasis on the therapeutic approaches with significant clinical benefits for pediatric AML.

How ITD Insertion Sites Orchestrate the Biology and Disease of FLT3-ITD-Mutated Acute Myeloid Leukemia

Mutations of the FLT3 gene are among the most common genetic aberrations detected in AML and occur mainly as internal tandem duplications (FLT3-ITD). However, the specific sites of FLT3-ITD insertion within FLT3 show marked heterogeneity regarding both biological and clinical features. In contrast to the common assumption that ITD insertion sites (IS) are restricted to the juxtamembrane domain (JMD) of FLT3, 30% of FLT3-ITD mutations insert at the non-JMD level, thereby integrating into various segments of the tyrosine kinase subdomain 1 (TKD1). ITDs inserted within TKD1 have been shown to be associated with inferior complete remission rates as well as shorter relapse-free and overall survival. Furthermore, resistance to chemotherapy and tyrosine kinase inhibition (TKI) is linked to non-JMD IS. Although FLT3-ITD mutations in general are already recognized as a negative prognostic marker in currently used risk stratification guidelines, the even worse prognostic impact of non-JMD-inserting FLT3-ITD has not yet been particularly considered. Recently, the molecular and biological assessment of TKI resistance highlighted the pivotal role of activated WEE1 kinase in non-JMD-inserting ITDs. Overcoming therapy resistance in non-JMD FLT3-ITD-mutated AML may lead to more effective genotype- and patient-specific treatment approaches.

Epigenomic machinery regulating pediatric AML: clonal expansion mechanisms, therapies, and future perspectives

Acute myeloid leukemia (AML) is a heterogeneous disease with a genetic, epigenetic, and transcriptional etiology mainly presenting somatic and germline abnormalities. AML incidence rises with age but can also occur during childhood. Pediatric AML (pAML) accounts for 15-20% of all pediatric leukemias and differs considerably from adult AML. Next-generation sequencing technologies have enabled the research community to "paint" the genomic and epigenomic landscape in order to identify pathology-associated mutations and other prognostic biomarkers in pAML. Although current treatments have improved the prognosis for pAML, chemoresistance, recurrence, and refractory disease remain major challenges. In particular, pAML relapse is commonly caused by leukemia stem cells that resist therapy. Marked patient-to-patient heterogeneity is likely the primary reason why the same treatment is successful for some patients but, at best, only partially effective for others. Accumulating evidence indicates that patient-specific clonal composition impinges significantly on cellular processes, such as gene regulation and metabolism. Although our understanding of metabolism in pAML is still in its infancy, greater insights into these processes and their (epigenetic) modulation may pave the way toward novel treatment options. In this review, we summarize current knowledge on the function of genetic and epigenetic (mis)regulation in pAML, including metabolic features observed in the disease. Specifically, we describe how (epi)genetic machinery can affect chromatin status during hematopoiesis, leading to an altered metabolic profile, and focus on the potential value of targeting epigenetic abnormalities in precision and combination therapy for pAML. We also discuss the possibility of using alternative epidrug-based therapeutic approaches that are already in clinical practice, either alone as adjuvant treatments and/or in combination with other drugs.

Clinical Outcomes of Acute Myeloid Leukemia Patients Harboring the RUNX1 Mutation: Is It Still an Unfavorable Prognosis? A Cohort Study and Meta-Analysis

Acute myeloid leukemia (AML) with mutated RUNX1 (RUNX1mut) is considered to have an unfavorable prognosis. However, recent studies have reported comparable survival outcomes with wild-type RUNX1 (RUNX1wt). To assess the clinical outcomes of AML with and without RUNX1mut, we performed a prospective cohort study and systematic review and meta-analysis. The study enrolled 135 patients (27 with RUNX1mut; 108 with RUNX1wt). There were no significant differences in the median OS and RFS of the RUNX1mut and RUNX1wt groups (9.1 vs. 12.2 months; p = 0.268 and 7.8 vs. 14.6 months; p = 0.481, respectively). A subgroup analysis of de novo AML patients with intermediate-risk cytogenetics showed similar outcomes. Our meta-analysis pooled data from 23 studies and our study. The complete remission rate was significantly lower in the RUNX1mut group (pooled odds ratio: 0.42). The OS, RFS, and event-free survival rates also favored the RUNX1wt group (pooled risk ratios: 1.36, 1.37, and 1.37, respectively). A subgroup analysis of de novo AML patients with intermediate-risk cytogenetics demonstrated nearly identical OS and RFS outcomes. This study confirms that patients with AML and RUNX1mut had poor prognoses. Nonetheless, in de novo AML with intermediate-risk cytogenetics, the survival outcomes of both groups were comparable.

A Phenogenetic Axis that Modulates Clinical Manifestation and Predicts Treatment Outcome in Primary Myeloid Neoplasms

Although the concept of "myeloid neoplasm continuum" has long been proposed, few comparative genomics studies directly tested this hypothesis. Here we report a multi-modal data analysis of 730 consecutive newly diagnosed patients with primary myeloid neoplasm, along with 462 lymphoid neoplasm cases serving as the outgroup. Our study identified a "Pan-Myeloid Axis" along which patients, genes, and phenotypic features were all aligned in sequential order. Utilizing relational information of gene mutations along the Pan-Myeloid Axis improved prognostic accuracy for complete remission and overall survival in adult patients of de novo acute myeloid leukemia and for complete remission in adult patients of myelodysplastic syndromes with excess blasts. We submit that better understanding of the myeloid neoplasm continuum might shed light on how treatment should be tailored to individual diseases.

Significance

The current criteria for disease diagnosis treat myeloid neoplasms as a group of distinct, separate diseases. This work provides genomics evidence for a "myeloid neoplasm continuum" and suggests that boundaries between myeloid neoplastic diseases are much more blurred than previously thought.

Pediatric Acute Myeloid Leukemia—Past, Present, and Future

This review reports about the main steps of development in pediatric acute myeloid leukemia (AML) concerning diagnostics, treatment, risk groups, and outcomes. Finally, a short overview of present and future approaches is given.

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.