A concise review on the molecular genetics of acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults that affects the myeloid lineage. The recent advances have upgraded our understanding of the cytogenetic abnormalities and molecular mutations associated with AML that further aids in prognostication and risk stratification of the disease. Based on the highly heterogeneous nature of the disease and cytogenetic profile, AML patients can be stratified into favourable, intermediate and adverse-risk groups. The recurrent genetic alterations provide novel insights into the pathogenesis, clinical characteristics and also into the overall survival of the patients. In this review we are discussing about the cytogenetics of AML and the recurrent gene alterations such us NPM1, FLT3, CEBPA, TET-2, c-KIT, DNMT3A, IDH, RUNX1, AXSL1, WT1, Ras gene mutations etc. These gene mutations serve as important prognostic markers as well as potential therapeutic targets. AML patients respond to induction chemotherapy initially and subsequently achieve complete remission (CR), eventually most of them get relapsed.

Novel insights of acute myeloid leukemia with CEBPA deregulation: Heterogeneity dissection and re-stratification

Acute myeloid leukemia with bi-allelic CEBPA mutation was categorized as an independent disease entity with favorable prognosis, however, recent researches have revealed huge heterogeneity within this disease group, and for some patients, relapse remained a major cause of treatment failure. Further risk stratification is essentially needed. Here by reviewing the latest literature, we summarized the characteristics of CEBPA mutation profiles and clinical features, with a special intention of dissecting the heterogeneity within the seemingly homogeneous AML with bi-allelic CEBPA mutations. Specifically, non-classical CEBPA mutation, miscellaneous companion genetic aberrations and the presence of germline CEBPA mutation are three major sources of heterogeneity. Identifying these factors can help us predict patients at a higher risk of relapse, for whom aggressive treatment may be recommended. Novel therapeutic approaches regarding manipulating potentially druggable targets as well as the debate over post remission consolidation regimens has also been discussed.

Acidic leucine-rich nuclear phosphoprotein-32A expression contributes to adverse outcome in acute myeloid leukemia

Background

Acidic leucine-rich nuclear phosphoprotein-32A (ANP32A) is a novel regulator of histone H3 acetylation and promotes leukemogenesis in acute myeloid leukemia (AML). However, its prognostic value in AML remains unclear.

Methods

In this study, we evaluated the prognostic significance of ANP32A expression using two independent large cohorts of cytogenetically normal AML (CN-AML) patients. Multivariable analysis in CN-AML group was also presented. Based on the ANP32A expression, its related genes, dysregulation of pathways, interaction network analysis between microRNAs and target genes, as well as methylation analysis were performed to unveil the complex functions behind ANP32A.

Results

Here we demonstrated overexpression of ANP32A was notably associated with unfavorable outcome in two independent cohorts of CN-AML patients (OS: P=0.012, EFS: P=0.005, n=185; OS: P=0.041, n=232), as well as in European Leukemia Net (ELN) Intermediate-I group (OS: P=0.018, EFS: P=0.045, n=115), National Comprehensive Cancer Network (NCCN) Intermediate Risk AML group (OS: P=0.048, EFS: P=0.039, n=225), and non-M3 AML group (OS: P=0.034, EFS: P=0.011, n=435). Multivariable analysis further validated ANP32A as a high-risk factor in CN-AML group. Multi-omics analysis presented overexpression of ANP32A was associated with aberrant expression of oncogenes and tumor suppressor, up/down-regulation of metabolic and immune-related pathways, dysregulation of microRNAs, and hypomethylation on CpG island and 1st Exon regions.

Conclusions

We proved ANP32A as a novel, potential unfavorable prognosticator and therapeutic target for AML.

Genetic Hierarchy of Acute Myeloid Leukemia: From Clonal Hematopoiesis to Molecular Residual Disease

Recent advances in the field of cancer genome analysis revolutionized the picture we have of acute myeloid leukemia (AML). Pan-genomic studies, using either single nucleotide polymorphism arrays or whole genome/exome next generation sequencing, uncovered alterations in dozens of new genes or pathways, intimately connected with the development of leukemia. From a simple two-hit model in the late nineties, we are now building clonal stories that involve multiple unexpected cellular functions, leading to full-blown AML. In this review, we will address several seminal concepts that result from these new findings. We will describe the genetic landscape of AML, the association and order of events that define multiple sub-entities, both in terms of pathogenesis and in terms of clinical practice. Finally, we will discuss the use of this knowledge in the settings of new strategies for the evaluation of measurable residual diseases (MRD), using clone-specific multiple molecular targets.

Expression and regulation of C/EBPα in normal myelopoiesis and in malignant transformation

One of the most studied transcription factors in hematopoiesis is the leucine zipper CCAAT-enhancer binding protein α (C/EBPα), which is mainly involved in cell fate decisions for myeloid differentiation. Its involvement in acute myeloid leukemia (AML) is diverse, with patients frequently exhibiting mutations, deregulation of gene expression, or alterations in the function of C/EBPα. In this review, we emphasize the importance of C/EBPα for neutrophil maturation, its role in myeloid priming of hematopoietic stem and progenitor cells, and its indispensable requirement for AML development. We discuss that mutations in the open reading frame of CEBPA lead to an altered C/EBPα function, affecting the expression of downstream genes and consequently deregulating myelopoiesis. The emerging transcriptional mechanisms of CEBPA are discussed based on recent studies. Novel insights on how these mechanisms may be deregulated by oncoproteins or mutations/variants in CEBPA enhancers are suggested in principal to reveal novel mechanisms of how CEBPA is deregulated at the transcriptional level.