Identification of acquired PIGA mutations and additional variants by next-generation sequencing in paroxysmal nocturnal hemoglobinuria

INTRODUCTION

Paroxysmal Nocturnal Hemoglobinuria (PNH) is an acquired clonal disease of hematopoietic stem cells. It is caused by somatic mutation of the X-linked PIGA gene, resulting in a deficient expression of glycosylphosphatidylinositol-anchored proteins (GPI-APs). In this study, we aimed to explore the diagnostic value of next-generation sequencing (NGS) and potential molecular basis in PNH patients.

METHODS

Genomic DNA of 85 PNH patients was analyzed by a 114-gene NGS panel.

RESULTS

Mutational analysis of PIGA identified 124 mutations in 92% PNH patients, including 101 distinct mutations and 23 recurrent mutations. Among them, 102 mutations were newly reported. Most mutations were located in exon 2 of PIGA gene, and truncated mutation was the most common one. Other mutations were detected in 26 out of 85 cases, including five cases of DNMT3A variants, four cases of ASXL1 variants, and four cases of U2AF1 variants. Clonal analysis was performed in one case and outlined a linear evolution pattern in classic PNH. There was a positive correlation between number of PIGA mutations and fraction of GPI-APs deficient granulocytes.

CONCLUSION

The detection of PIGA mutations and additional variants by targeted NGS not only shed light on the genetic characteristics of PNH, but also provided an important reference value in the diagnosis of PNH at molecular level.

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.

Impact of the variant allele frequency of ASXL1, DNMT3A, JAK2, TET2, TP53, and NPM1 on the outcomes of patients with newly diagnosed acute myeloid leukemia

BACKGROUND

The impact of the allelic burden of ASXL1, DNMT3A, JAK2, TET2, and TP53 mutations on survival remains unclear in patients with newly diagnosed acute myeloid leukemia (AML).

METHODS

The authors assessed bone marrow aspirates from 421 patients with newly diagnosed AML using next-generation sequencing for ASXL1, DNMT3A, JAK2, TET2, and TP53 mutations, defined as the presence of mutations in ASXL1, DNMT3A, JAK2, TET2, or TP53 with a minimum variant allele frequency (VAF) of 5%.

RESULTS

A total of 71 patients (17%) had ASXL1 mutations, 104 patients (25%) had DNMT3A mutations, 16 patients (4%) had JAK2 mutations, 82 patients (20%) had TET2 mutations, and 86 patients (20%) had TP53 mutations. Among patients with each mutation, the median VAF of ASXL1 was 34.31% (range, 1.17%-58.62%), the median VAF of DNMT3A was 41.76% (range, 1.02%-91.66%), the median VAF of JAK2 was 46.70% (range, 10.4%-71.7%), the median VAF of TET2 was 42.78% (range, 2.26%-95.32%), and the median VAF of TP53 was 45.47% (range, 1.15%-93.74%). The composite complete response rate was 60%, and was 77% in patients with AML with and without ASXL1, DNMT3A, JAK2, TET2, or TP53 mutations, respectively (P = .006); the median overall survival was 11 months and 27 months, respectively (P < .001). Multivariate analysis identified age; an antecedent history of dysplasia; white blood cell count; adverse cytogenetic risk; previous treatment with an FLT3 inhibitor; and the VAF of ASXL1, DNMT3A, JAK2, TET2, TP53, and NPM1 mutations by next-generation sequencing as prognostic factors for overall survival.

CONCLUSIONS

The VAF of ASXL1, DNMT3A, JAK2, TET2, TP53, and NPM1 mutations is associated with worse prognosis in patients with newly diagnosed AML.

Remethylation of Dnmt3a -/- hematopoietic cells is associated with partial correction of gene dysregulation and reduced myeloid skewing

Mutations that reduce the function of the de novo DNA methyltransferase, DNMT3A, are very common in patients with clonal hematopoiesis and hematopoietic malignancies. Restoring the function of DNMT3A in mouse hematopoietic cells deficient for this protein corrects the DNA methylation defect in an ordered fashion, and partially restores abnormalities in gene expression and myeloid population skewing. These data may be relevant for therapeutic strategies designed to restore DNMT3A activity in patients with diseases caused by mutations in this gene.

Mutations in the DNA methyltransferase 3A (DNMT3A) gene are the most common cause of age-related clonal hematopoiesis (ARCH) in older individuals, and are among the most common initiating events for acute myeloid leukemia (AML). The most frequent DNMT3A mutation in AML patients (R882H) encodes a dominant-negative protein that reduces methyltransferase activity by ∼80% in cells with heterozygous mutations, causing a focal, canonical DNA hypomethylation phenotype; this phenotype is partially recapitulated in murine Dnmt3a^−/− bone marrow cells. To determine whether the hypomethylation phenotype of Dnmt3a^−/− hematopoietic cells is reversible, we developed an inducible transgene to restore expression of DNMT3A in transplanted bone marrow cells from Dnmt3a^−/− mice. Partial remethylation was detected within 1 wk, but near-complete remethylation required 6 mo. Remethylation was accurate, dynamic, and highly ordered, suggesting that differentially methylated regions have unique properties that may be relevant for their functions. Importantly, 22 wk of DNMT3A addback partially corrected dysregulated gene expression, and mitigated the expansion of myeloid cells. These data show that restoring DNMT3A expression can alter the epigenetic “state” created by loss of Dnmt3a activity; this genetic proof-of-concept experiment suggests that this approach could be relevant for patients with ARCH or AML caused by loss-of-function DNMT3A mutations.

Combining gene variants with clinical characteristics improves outcome prediction in Chinese patients with myelodysplastic syndromes

Genetic variants have been identified in the majority of myelodysplastic syndromes (MDS) patients and have considerably influenced the diagnosis, classification, risk stratification and treatment of MDS. To explore the prognostic significance of genomic variants and build a new prognostic scoring model, we performed next-generation sequencing of 51 known genes in 499 Chinese patients with MDS. Ultimately, the TP53, GATA2, DNMT3A, age and the revised International Prognostic Scoring System (IPSS-R) risk stratification were included in a new Cox model and divided into three prognostic categories, and had a better prediction of overall survival. The C-index of the new prognostic scoring model (0.772) was clearly better than IPSS-R risk stratification (0.717), which was validated in 163 cases. Moreover, the new model was also suitable for the prediction of OS for patients undergoing allogeneic hematopoietic stem cell transplantation. The inclusion of genomic variants and age into the IPSS-R could improve prognostic algorithms for MDS patients.

Identification of Two DNMT3A Mutations Compromising Protein Stability and Methylation Capacity in Acute Myeloid Leukemia

Somatic mutations of DNMT3A occur in about 20% of acute myeloid leukemia (AML) patients. They mostly consist in heterozygous missense mutations targeting a hotspot site at R882 codon, which exhibit a dominant negative effect and are associated with high myeloblast count, advanced age, and poor prognosis. Other types of mutations such as truncations, insertions, or single-nucleotide deletion also affect the DNMT3A gene, though with lower frequency. The present study aimed to characterize two DNMT3A gene mutations identified by next-generation sequencing (NGS), through analysis of protein stability and DNA methylation status at CpG islands. The first mutation was a single-nucleotide variant of DNMT3A at exon 20 causing a premature STOP codon (c.2385G > A; p.Trp795 ^∗ ; NM_022552.4). The DNMT3A mutation load increased from 4.5% to 38.2% during guadecitabine treatment, with a dominant negative effect on CpG methylation and on protein expression. The second mutation was a novel insertion of 35 nucleotides in exon 22 of DNMT3A (NM_022552.4) that introduced a STOP codon too, after the amino acid Glu863 caused by a frameshift insertion (c.2586_2587insTCATGAATGAGAAAGAGGACATCTTATGGTGCACT; p. Thr862_Glu863fsins). The mutation, which was associated with reduced DNMT3A expression and CpG methylation, persisted at relapse with minor changes in the methylation profile and at protein level. Our data highlight the need to better understand the consequences of DNMT3A mutations other than R882 substitutions in the leukemogenic process in order to tailor patient treatments, thus avoiding therapeutic resistance and disease relapse.

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.

Insights into novel emerging epigenetic drugs in myeloid malignancies

Epigenetics has been defined as ‘a stably heritable phenotype resulting from changes in a chromosome without alterations in the DNA sequence’ and several epigenetic regulators are recurrently mutated in hematological malignancies. Epigenetic modifications include changes such as DNA methylation, histone modifications and RNA associated gene silencing. Transcriptional regulation, chromosome stability, DNA replication and DNA repair are all controlled by these modifications. Mutations in genes encoding epigenetic modifiers are a frequent occurrence in hematologic malignancies and important in both the initiation and progression of cancer. Epigenetic modifications are also frequently reversible, allowing excellent opportunities for therapeutic intervention. The goal of epigenetic therapies is to reverse epigenetic dysregulation, restore the epigenetic balance, and revert malignant cells to a more normal condition. The role of epigenetic therapies thus far is most established in hematologic malignancies, with several agents already approved by the US Food and Drug Administration. In this review, we discuss pharmacological agents targeting epigenetic regulators.

High Expression Levels of ACTN1 and ACTN3 Indicate Unfavorable Prognosis in Acute Myeloid Leukemia

Background: Actinins are major cytoskeletal proteins that mediate sarcomere function, and they also have important non-muscle functions such as regulating cytokinesis, cell adhesion and migration. There are four isoforms of actinins in mammals (ACTN1-4). Recently, the relationship between actinins and cancer has been discovered in many types of malignancy, yet their prognostic significance in acute myeloid leukemia (AML) remains unclear. Methods: We collected data of 155 de novo AML patients from The Cancer Genome Atlas (TCGA) database; 85 patients received chemotherapy only and 70 patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). We divided each treatment groups into sub-groups based on the median expression levels of ACTN1-4. Results: Survival analysis showed that in the chemotherapy-only group, high ACTN1 and ACTN3 expression were associated with shorter event-free survival (EFS) and overall survival (OS) (p<0.01). Multivariate analysis suggested that high expression of ACTN1 and ACTN3 (p<0.05) were independent poor prognostic factors. In the allo-HSCT group, ACTN1-4 expression had no impact on survival. Conclusions: Our study suggested that high expression levels of ACTN1 and ACTN3 adversely affected the survival of AML patients, but their harmful impact could be overcome by allo-HSCT.

Low Platelet Counts at Diagnosis Predict Better Survival for Patients with Intermediate-Risk Acute Myeloid Leukemia

BACKGROUND

Aggressive growth of primitive and immature cells in the bone marrow results in reductions in megakaryocyte and platelet (PLT) counts, leading to thrombocytopenia in acute myeloid leukemia (AML). However, not all AML patients show thrombocytopenia at the time of diagnosis, and the association of PLT count with patient survival is largely unknown.

METHODS

A retrospective study was performed to determine PLT counts at diagnosis in the peripheral blood in 291 newly diagnosed AML patients and assess the association of PLT counts with the overall survival (OS) and disease-free survival (DFS) of these patients.

RESULTS

Low PLT counts (≤40 × 109/L) were associated with better outcomes for the whole cohort (5-year OS, 55.1 ± 3.8 vs. 35.3 ± 3.5%, p < 0.001; 5-year DFS, 49.1 ± 3.8 vs. 25.7 ± 4.0%, p < 0.001) and intermediate-risk patients (5-year OS, 64.5 ± 5.4 vs. 41.0 ± 4.8%, p < 0.001; 5-year DFS, 60.8 ± 5.6 vs. 28.6 ± 5.6%, p < 0.001). Moreover, low PLT counts were related to deeper molecular remission. Low PLT counts correlated with better survival of intermediate-risk AML patients treated with chemotherapy only. Allogeneic hematopoietic stem cell transplantation attenuated the negative impact of high PLT counts on the survival of intermediate-risk patients. Furthermore, univariate and multivariate analyses demonstrated that PLT count at diagnosis was an independent prognostic factor for intermediate-risk AML.

CONCLUSION

PLT count at diagnosis predicts survival for patients with intermediate-risk AML.

High NCALD expression predicts poor prognosis of cytogenetic normal acute myeloid leukemia

Background

Acute myeloid leukemia (AML) is a heterogeneous disease in terms of genetic basis, clinical, biological and prognostic, and is a malignant clonal disease of leukemia stem cells (LSCs). Nearly half of adult AML patients exhibit a cytogenetic normal acute myeloid leukemia (CN-AML). The expression level of NCALD gene was associated with the prognosis of ovarian cancer and non-small cell lung cancer (NSCLC). The expression level of NCALD gene is still unclear in the prognosis of patients with AML.

Method

We integrated 5 independent datasets totally 665 AML patients (497 CN-AML patients) to analyzed relation between NCALD gene expression and the clinical FAB classification, gene mutation, therapy, prognosis of CN-AML. We analyzed the NCALD gene expression with the prognosis and LSC of 165 AML patients from The Cancer Genome Atlas (TCGA) dataset and 78 AML patients from GEO dataset.

Results

High NCALD-expressing CN-AML patients were associated with poor event-free survival (EFS) and overall survival (OS) compared to low NCALD expression (EFS, P < 0.0001, OS, P < 0.0001). In AML patients of allogeneic hematopoietic stem cell transplantation (allo-HSCT), high NCALD expression was associated with poor survival prognosis in EFS and OS (EFS, P < 0.0051, OS, P = 0.028). Post-chemotherapy in AML patients, high NCALD expression led a worse prognosis in EFS and OS (EFS, P = 0.011; OS, P = 0.0056). In multivariate analysis, high NCALD expression was an independent prognostic factor that predicts shorter EFS and OS (EFS, P = 3.84E−05, OS, P = 8.53E−05) of CN-AML.

Conclusion

Our results indicate that high expression of NCALD gene is a poor prognostic factor for CN-AML. NCALD can be considered as independent predictors of CN-AML patients and can be used as a biomarker for the prognosis of CN-AML.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1904-5) contains supplementary material, which is available to authorized users.

Acute myeloid leukemia patient with FLT3-ITD and NPM1 double mutation should undergo allogeneic hematopoietic stem cell transplantation in CR1 for better prognosis

Background: According to the recent National Comprehensive Cancer Network (NCCN) guidelines, the risk level in acute myeloid leukemia (AML) patients with FLT3-ITD and NPM1 double mutation (AML ^{FLT3-ITD+/NPM1+} ) depends on the allelic ratio of FLT3-ITD. But despite a low or high allelic ratio of FLT3-ITD, AML ^{FLT3-ITD+/NPM1+} patients belong to the favorable or intermediate risk, for whom allogeneic stem cell transplantation is not obligated. However, some latest studies pointing out that NPM1 and FLT3-ITD double mutation patients showed an inferior prognosis, which have raised concern about the risk categorization and more effective treatment of AML ^{FLT3-ITD+/NPM1+} patients. Methods: A total of 76 patients were selected for coexisting FLT3 and NPM1 mutations with normal cytogenetics. The prognostic risk factors were analyzed, and treatment strategies including allogeneic stem cell transplantati1on and chemotherapy were compared. Results: In 76 AML ^{FLT3-ITD+/NPM1+} patients, 36.8% of patients had hyperleukocytosis (HL) and DNMT3A R882 mutation was the most common concomitant gene (23.7%). For 53 patients in the complete remission (CR), 22 had received allogeneic hematopoietic stem cell transplantation (allo-HSCT) on first complete remission (CR1). Patients in transplantation group had better overall survival (OS) and disease-free survival (DFS) than chemotherapy only (P=0.002 and 0.001, respectively). In multivariable Cox model analyses, HL and DNMT3A R882 mutation were independent adverse prognostic factors (all P<0.05) for AML ^{FLT3-ITD+/NPM1+} patients. Nevertheless, allo-HSCT was an independent good factor of OS and DFS (P=0.001 and 0.000; HR =0.173 and 0.138; 95% CI were 0.062-0.483 and 0.049-0.389). And allo-HSCT could moderately improve the poor prognosis of AML ^{FLT3-ITD+/NPM1+/DNMT3A R882+}. Conclusion: Although, AML ^{FLT3-ITD+/NPM1+} patients are categorized as favorable or intermediate risk levels according to recent NCCN and ELN guidelines, these patients should receive allo-HSCT in CR1 for a longer survival. AML ^{FLT3-ITD+/NPM1+} patients with DNMT3A R882 mutation had a very poor prognosis, and allo-HSCT could moderately improve their survival.

Clinical Effect of Combined Mutations in DNMT3A, FLT3-ITD, and NPM1 Among Egyptian Acute Myeloid Leukemia Patients

BACKGROUND

Genotypic mutation of fms like tyrosine kinase 3 (FLT3), Nucleophosmin (NPM1), and DNA-methyltransferase 3A (DNMT3A) has been involved in the leukemogenesis of acute myeloid leukemia (AML), with the well known poor prognostic role of FLT3 and DNMT3A and favorable role for the NPM1 mutation.

PATIENTS AND METHODS

A total of 123 patients with AML treated at the National Cancer Institute, Cairo University were examined for mutations in DNMT3A, FLT3, and NPM1 using polymerase chain reaction (PCR) for detecting FLT3 internal tandem duplication (ITD) and allele-specific PCR to detect DNMT3A and NPM1A mutations. Two-way direct sequencing and Gene Mapper version 4.0 software (Fred Hutchinson Cancer Research Center) sequencing were used as confirmatory tests for DNMT3A and NPM1A mutations, respectively.

RESULTS

DNMT3A, FLT3-ITD, and NPM1A gene mutations were detected in 22 (17.9%), 22 (17.9%), and 24 (19.5%) patients, respectively. DNMT3A/FLT3, NPM1A/FLT3, and DNMT3A/NPM1A combined mutant genotypes were detected in 5 (4.1%), 9 (7.3%), and 3 (2.4%) patients, respectively. Two patients (1.6%) had triple mutant genotypes (DNMT3A/FLT3/NPM1A). FLT3 and DNMT3A mutations had a significant negative effect on complete response (CR) rates (P = .016). FLT3-ITD mutation was significantly associated with older age (P = .029), and lower overall survival (OS) rates (P = .046). DNMT3A/FLT3 combined mutant genotypes were significantly associated with a lower OS rate (P = .016). Mutant NPM1/wild type FLT3, wild type DNMT3A/FLT3, and mutant NPM1A/wild type DNMT3A combinations were significantly associated with higher CR rates (P = .006, P = .006, and P = .023, respectively).

CONCLUSION

DNMT3A, FLT3-ITD, and NPM1A are frequent mutations in Egyptian AML. FLT3-ITD mutations are frequent in older patients. DNMT3A and FLT3-ITD mutations were associated with an unfavorable prognosis, but the NPM1A mutation has tendency to indicate a good prognosis.

DNA methylation as a transcriptional regulator of the immune system

DNA methylation is a dynamic epigenetic modification with a prominent role in determining mammalian cell development, lineage identity, and transcriptional regulation. Primarily linked to gene silencing, novel technologies have expanded the ability to measure DNA methylation on a genome-wide scale and uncover context-dependent regulatory roles. The immune system is a prototypic model for studying how DNA methylation patterning modulates cell type- and stimulus-specific transcriptional programs. Preservation of host defense and organ homeostasis depends on fine-tuned epigenetic mechanisms controlling myeloid and lymphoid cell differentiation and function, which shape innate and adaptive immune responses. Dysregulation of these processes can lead to human immune system pathology as seen in blood malignancies, infections, and autoimmune diseases. Identification of distinct epigenotypes linked to pathogenesis carries the potential to validate therapeutic targets in disease prevention and management.

Epigenetic Erosion in Adult Stem Cells: Drivers and Passengers of Aging

In complex organisms, stem cells are key for tissue maintenance and regeneration. Adult stem cells replenish continuously dividing tissues of the epithelial and connective types, whereas in non-growing muscle and nervous tissues, they are mainly activated upon injury or stress. In addition to replacing deteriorated cells, adult stem cells have to prevent their exhaustion by self-renewal. There is mounting evidence that both differentiation and self-renewal are impaired upon aging, leading to tissue degeneration and functional decline. Understanding the molecular pathways that become deregulate in old stem cells is crucial to counteract aging-associated tissue impairment. In this review, we focus on the epigenetic mechanisms governing the transition between quiescent and active states, as well as the decision between self-renewal and differentiation in three different stem cell types, i.e., spermatogonial stem cells, hematopoietic stem cells, and muscle stem cells. We discuss the epigenetic events that channel stem cell fate decisions, how this epigenetic regulation is altered with age, and how this can lead to tissue dysfunction and disease. Finally, we provide short prospects of strategies to preserve stem cell function and thus promote healthy aging.

From cellular morphology to molecular and epigenetic anomalies of myelodysplastic syndromes

Myelodysplastic syndromes (MDSs) are a myeloid neoplasm with a propensity for natural evolution or transformation to acute leukemias (AL) over time. Mechanisms for MDS transformation to AL remain poorly understood but are related to genomic instability, which affects the production of the different cell lineages. Genomic instability is also generated by dysfunctional telomeres. Indeed telomeres, the protective ends of chromosomes are the backbone of genome stability. Nuclear telomere remodeling is an early indicator of nuclear remodeling preceding the onset of genomic instability and MDS. This review aims to revisit the pathogenesis and pathophysiology of MDS from morphology and cytogenetics to molecular and epigenetic mechanisms. Furthermore, this review will highlight and discuss recent breakthroughs in dysfunctional telomeres and nuclear telomere architecture roles in the pathogenesis and physiopathology of MDS in the global context of genomic instability.

Genetic and Epigenetic Perturbations by DNMT3A-R882 Mutants Impaired Apoptosis through Augmentation of PRDX2 in Myeloid Leukemia Cells

DNA methyltransferase 3A (DNMT3A) is mutated in various myeloid neoplasms including acute myeloid leukemia (AML), especially at the Arg882 and associated with inferior outcomes. Here, we report that the DNMT3A-Arg882His/Cys (R882H/C) mutations led to inactivation of apoptosis through DNA damage signaling following the impairment of differentiation of myeloid leukemia cells. Gene expression profiling analysis revealed aberrant expression of several cell-cycle and apoptosis-related genes, and the DNA methylation assay identified both hypo- and hypermethylation features in different regions throughout the whole genome of DNMT3A mutants-transduced myeloid cells. We found that DNMT3A-R882H/C mutations upregulated the expression of an antioxidant protein, pyroxiredoxin-2 (PRDX2), at the mRNA and protein levels with decreased accumulation of reactive oxygen species (ROS). Augmentation of ROS generation by ROS accumulating agent or by knockdown of PRDX2 from myeloid cells effectively increased drug sensitivity and apoptosis as a consequence of reduced cell proliferation. DNMT3A-R882C/H mutations decreased apoptosis induction in part by increasing the antioxidant capacity of the cell owing to upregulation of PRDX2. Molecularly, both DNMT3A-WT and R882H/C mutants interacted with PRDX2; and R882C/H mutation-induced hypomethylation increased PRDX2 expression which enhanced cell proliferation and growth with impairment of apoptosis, thereby contributing to leukemogenesis.

Genetic Landscape of Acute Myeloid Leukemia Interrogated by Next-generation Sequencing: A Large Cancer Center Experience

BACKGROUND/AIM

Acute myeloid leukemia (AML) represents a heterogeneous disease with varying morphologic, immunophenotypic, and genetic features, along with varying patient outcomes. The genomic tractability of AML makes it amenable for targeted next-generation sequencing (NGS) testing clinically.

MATERIALS AND METHODS

One hundred eights-seven unique patients with a diagnosis of acute myeloid leukemia between May 2011 and Oct 2014 and with mutational analysis by NGS were included in this study. The distribution of gene mutations was investigated in different subcategories of AML.

RESULTS

Most patients in this study (n=182) received Genoptix testing (either 5-gene panel or 21-gene panel). In 130/187 (70%) cases, there was an average of 2.3 mutations per case (range=0-7 mutations). We specifically mention mutations in 32 genes, their significance and co-occurrence as detected in different types of AML.

CONCLUSION

The genetic heterogeneity of AML signifies the importance of taking a personalized-medicine approach to the management of patients with AML.

Biological and clinical influences of NPM1 in acute myeloid leukemia patients with DNMT3A mutations

Purpose

DNMT3A and NPM1 mutations are known to impact the prognosis of acute myeloid leukemia (AML). DNMT3A mutations are negative prognostic factors, while NPM1 mutations are low-risk factors and inclined to concurrently appear with DNMT3A mutations. In this study, we aimed to find out how NPM1 mutations affect patients’ outcomes in the background of DNMT3A mutations.

Patients and methods

We screened The Cancer Genome Atlas (TCGA) database and found 51 AML patients with DNMT3A mutations. Of them, 28 patients had a combination of NPM1 mutations.

Results

In all, NPM1 had the highest mutation frequency (n=28, 54.9%). DNMT3A^mut/NPM1^mut patients had higher bone marrow (BM) blasts (P=0.015), higher FLT3-ITD/TKD rate (P=0.004), and lower IDH2 mutation rate (P=0.014) than the DNMT3A^mut/NPM1^wild patients, while their prognoses were the same as the DNMT3A^mut/NPM1^wild patients (P>0.1). All 51 patients benefited from hematopoietic stem cell transplantation (HSCT) treatment (P=0.005 and 0.001 for event-free survival [EFS] and overall survival [OS], respectively). In the 23 patients with DNMT3A^mut/NPM1^wild, those who received HSCT had prolonged EFS and OS (P=0.043 and 0.008, respectively), while HSCT treatment did not produce a positive impact on EFS and OS in the remaining 28 patients with DNMT3A^mut/NPM1^mut (P=0.056 and 0.053, respectively).

Conclusion

Our study found that NPM1 mutations influenced BM blasts’ percentage, FLT3-ITD/TKD rate, and IDH2 mutation rate in AML patients with DNMT3A mutations but made little difference to the overall prognosis. While HSCT treatments benefited all DNMT3A^mut patients, it was better for DNMT3A^mut/NPM1^wild patients to extend their EFS and OS.

Clinical and biological implications of IDH1/2 in acute myeloid leukemia with DNMT3Amut

Purpose

The incidence of DNMT3A mutations in acute myeloid leukemia (AML) is quite high and often confers a poorer prognosis. Another common gene involved in AML is IDH1/2. However, the influence of IDH1/2 mutations on outcomes in DNMT3A-mutated patients remains unknown. This study aims to determine the effect of IDH1/2^mut on the prognosis in patients with DNMT3A-mutated AML.

Patients and methods

We screened patients from The Cancer Genome Atlas database and selected 51 patients with AML and the DNMT3A mutation, among which 16 patients (31.4%) had both DNMT3A and IDH1/2^mut.

Results

Among our sample, 11 cases had the IDH1 mutation (21.7%), and 5 cases had the IDH2 mutation (9.8%). Patients in the DNMT3A^mutIDH1/2^wild group showed a greater number of NPM1 mutation (P=0.022), and higher event-free survival (EFS) and overall survival (OS) after hematopoietic stem cell transplantation (HSCT) (P=0.010 and P=0.007, respectively). Patients in the DNMT3A^mutIDH1/2^mut group showed no increase in EFS or OS after HSCT or chemotherapy. Other factors, like white blood cells, bone marrow blasts, peripheral blood blasts, and mutated recurrent gene numbers had no significant influence on EFS and OS.

Conclusion

The IDH1/2 gene had little influence on the prognosis of patients with the DNMT3A mutation. For patients in the DNMT3A^mutIDH1/2^wild group, HSCT had a more favorable therapeutic effect. For patients with DNMT3A and IDH1/2^mut, chemotherapy and HSCT appeared to have similar efficacy.

Epigenetics in myelodysplastic syndromes

Epigenetic regulators are the largest group of genes mutated in MDS patients. Most mutated genes belong to one of three groups of genes with normal functions in DNA methylation, in H3K27 methylation/acetylation or in H3K4 methylation. Mutations in the majority of epigenetic regulators disrupt their normal function and induce a loss-of-function phenotype. The transcriptional consequences are often failure to repress differentiation programs and upregulation of self-renewal pathways. However, the mechanisms how different epigenetic regulators result in similar transcriptional consequences are not well understood. Hypomethylating agents are active in higher risk MDS patients, but their efficacy does not correlate with mutations in epigenetic regulators and the median duration of hematologic response is limited to 10-13 months. Inhibitors of histone deacetylases (HDAC) yielded disappointing results so far, questioning this approach in MDS patients. We review the clinical relevance of epigenetic mutations in MDS, discuss their functional consequences and highlight the role of epigenetic therapies in this difficult to treat disease.

FLT3-ITD Compared with DNMT3A R882 Mutation Is a More Powerful Independent Inferior Prognostic Factor in Adult Acute Myeloid Leukemia Patients After Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Cohort Study

Objective

This study aimed to evaluate DNMT3A exon 23 mutations and their prognostic impacts in the presence of NPM1 and FLT3 mutations in acute myeloid leukemia (AML) patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT).

Materials and Methods

This study comprised 128 adult AML patients referred to the Hematology-Oncology and Stem Cell Research Center of Shariati Hospital. NPM1 and FLT3-ITD mutations were detected by fragment analysis. For DNMT3A exon 23 mutation analysis, we used Sanger sequencing. Overall survival (OS) and relapse-free survival (RFS) curves were estimated by the Kaplan-Meier method and the log-rank test was used to calculate differences between groups.

Results

The prevalence of DNMT3A exon 23 mutations was 15.6% and hotspot region R882 mutations were prominent. RFS and OS were compared in patients with and without DNMT3A exon 23 mutations using univariate analysis and there was no significant difference between these groups of patients. On the contrary, the FLT3-ITD mutation significantly reduced the OS (p=0.009) and RFS (p=0.006) in AML patients after allogeneic HSCT. In the next step, patients with AML were divided into four groups regarding FLT3-ITD and DNMT3A mutations. Patients with DNMT3A R882mut/FLT3-ITDpos had the worst OS and RFS. These results indicate that DNMT3A mutations alone do not affect the clinical outcomes of AML patients undergoing allogeneic HSCT, but when accompanied by FLT3-ITD mutations, the OS was significantly reduced (5-year OS 0% for DNMT3A R882mut/FLT3-ITDpos patients vs. 62% DNMT3A R882wt/FLT3-ITDneg, p=0.025) and the relapse rate increased.

Conclusion

It can be deduced that DNMT3A R882mut/FLT3-ITDpos is an unfavorable prognostic factor in AML patients even after allogeneic HSCT.

NKp30 expression is a prognostic immune biomarker for stratification of patients with intermediate-risk acute myeloid leukemia

Cytogenetics and European Leukemia Net (ELN) genetic classification predict patients at increased risk of relapse in acute myeloid leukemia (AML) except in the intermediate risk group for which further prognostic determinants are required. We have previously shown that Natural Killer (NK) cell defects in AML are predictors of poor overall survival (OS). This study aimins at validating NKp30, a receptor that mediates NK activation, as a prognostic biomarker for AML patients with intermediate prognosis.

NKp30 expression was prospectively assessed at diagnosis on NK cells from peripheral blood by flow cytometry (N = 201 patients). Clinical outcome was evaluated with regard to NKp30 status.

In patients with intermediate cytogenetic (N = 162), NKp30^high phenotype at diagnosis was predictive of better OS (HR = 0.26; 95%CI = [0.14-0.50]; P < 0.0001) and relapse-free survival (RFS) (HR = 0.21; 95%CI = [0.08-0.52]; P = 0.0007). In patients with intermediate ELN (N = 116), NKp30^high phenotype at diagnosis was predictive of better OS (HR = 0.33; 95%CI = [0.16–0.67]; P = 0.0019) and RFS (HR = 0.24; 95%CI = [0.08-0.67]; P = 0.0058). In multivariate analysis, high NKp30 expression independently predicted improved OS (HR = 0.56, P = 0.046) and RFS (HR = 0.37, P = 0.048). Consistently, cumulative incidence of relapse (CIR) was lower in patients with high NKp30 expression (HR = 0.37, P = 0.026).

In conclusion, we propose NKp30 status as a simple and early prognostic biomarker that identifies intermediate-risk patients with poor prognosis who otherwise may not be identified with existing risk stratification systems.

Dynamics of DNMT3A mutation and prognostic relevance in patients with primary myelodysplastic syndrome

Background

DNMT3A gene mutation has been associated with poor prognosis in acute myeloid leukemia, but its clinical implications in myelodysplastic syndrome (MDS) and dynamic changes during disease progression remain controversial.

Results

In this study, DNMT3A mutation was identified in 7.9% of 469 de novo MDS patients. DNMT3A-mutated patients had higher platelet counts at diagnosis, and patients with ring sideroblasts had the highest incidence of DNMT3A mutations, whereas those with multilineage dysplasia had the lowest incidence. Thirty-one (83.8%) of 37 DNMT3A-mutated patients had additional molecular abnormalities at diagnosis, and DNMT3A mutation was highly associated with mutations of IDH2 and SF3B1. Patients with DNMT3A mutations had a higher risk of leukemia transformation and shorter overall survival. Further, DNMT3A mutation was an independent poor prognostic factor irrespective of age, IPSS-R, and genetic alterations. The sequential study demonstrated that the original DNMT3A mutations were retained during follow-ups unless allogeneic hematopoietic stem cell transplantation was performed, while DNMT3A mutation was rarely acquired during disease progression.

Conclusions

DNMT3A mutation predicts unfavorable outcomes in MDS and was stable during disease evolutions. It may thus be a potential biomarker to predict prognosis and monitor the treatment response.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0476-1) contains supplementary material, which is available to authorized users.

Novel impact of the DNMT3A R882H mutation on GSH metabolism in a K562 cell model established by TALENs

DNA methyltransferase 3A (DNMT3A) mutations occurred in 18%~23% of acute myeloid leukemia (AML) patients, and were considered to be an adverse prognostic factor for adult de novo AML cases. However, the relevant molecular mechanism of the mutation in AML pathogenesis remains obscure. In this study, we established K562 and SKM1 cell model carrying the DNMT3A R882H mutation via transcription activator-like effector nuclease (TALEN) and Clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) technology, and discovered that mutated DNMT3A could promote the proliferative capability of malignant cell clones. Further RNA microarray analysis revealed that some genes crucial for glutathione (GSH) synthesis, including CTH, PSPH, PSAT1 and especially SLC7A11 (the cysteine/glutamate transporter) were significantly up-regulated, which resulted in significant elevation of intracellular GSH levels. A subsequent experiment demonstrated that the mutant clones are resistant to chemotherapy as well as SLC7A11-inhibitorsBy shRNA induced SLC7A11 silencing, we discovered profoundly decreased cellular GSH and cell proliferative ability of DNMT3A mutated clones. Our results provided novel insight into the role of the DNMT3A R882H mutation in AML pathogenesis and suggested that targeting the cellular GSH synthetic pathway could enhance the current therapy for AML patients with the DNMT3A R882H mutation.

Molecular characteristic of acute leukemias with t(16;21)/FUS-ERG

T(16;21)(p11;q22)/FUS-ERG is a rare but recurrent translocation in acute leukemias and in some types of solid tumors. Due to multiple types of FUS-ERG transcripts, PCR-based minimal residual disease detection is impeded. In this study, we evaluated a cohort of pediatric patients with t(16;21)(p11;q22)/FUS-ERG and revealed fusion gene breakpoints. We implemented next-generation sequencing (NGS) on long PCR amplicons for the detection of fusion genes with unknown partners or DNA breakpoints. That allowed us to describe different fusion variants of FUS/ERG in different patients and to detect MRD on both RNA and DNA levels. We also found several accompanying mutations in epigenetic regulators (DNMT3A, ASXL1, BCOR) by targeted NGS approach in AML cases. These mutations preceded full transformation by t(16;21)(p11;q22)/FUS-ERG and allowed us to trace clonal evolution on all steps of therapy. As a casual observation, the ASXL1 mutation was found in the unrelated donor hematopoietic cells.

Mutation profiling of 19 candidate genes in acute myeloid leukemia suggests significance of DNMT3A mutations

We selected 19 significantly-mutated genes in AMLs, including FLT3, DNMT3A, NPM1, TET2, RUNX1, CEBPA, WT1, IDH1, IDH2, NRAS, ASXL1, SETD2, PTPN11, TP53, KIT, JAK2, KRAS, BRAF and CBL, and performed massively parallel sequencing for 114 patients with acute myeloid leukemias, mainly including those with normal karyotypes (CN-AML). More than 80% of patients had at least one mutation in the genes tested. DNMT3A mutation was significantly associated with adverse outcome in addition to conventional risk stratification such as the European LeukemiaNet (ELN) classification. We observed clinical usefulness of mutation testing on multiple target genes and the association with disease subgroups, clinical features and prognosis in AMLs.

Clonal Hematopoiesis of Indeterminate Potential

BACKGROUND

Patients with cytopenia are increasingly undergoing molecular genetic tests of periperal blood or bone marrow for diagnostic purposes. These tests can detect genetic mutations that do not have any morphological correlate in hematologic neoplasia such as myelo - dysplastic syndrome (MDS). A new entity was recently defined to lessen the risk of incorrect diagnoses of MDS. This new entity is a potential precursor of myeloid diseases, analogously to monoclonal gammopathy of undetermined significance as a potential precursor of multiple myeloma.

METHODS

This review is based on pertinent articles retrieved by a selective search in PubMed employing the terms "clonal hematopoiesis," "acute myeloid leukemia," and "myelodysplastic syndrome."

RESULTS

Clonal hematopoiesis of indeterminate potential (CHIP) is a new entity in which somatic mutations are found in cells of the blood or bone marrow, but no other criteria for hematologic neoplasia are met. Its prevalence rises with age and is roughly 10% among persons aged 70 to 80. It is estimated that, in Germany, about 2.75 million people are affected. The most common mutation is on the DNMT3A gene, followed by TET2 and ASXL1. The rate of transformation to a hematological neoplasia is 0.5-1% per year, and thus about 13 times higher than the incidence of such neoplasias in general. If CHIP is discovered incidentally in a patient with a normal blood count, a complete blood count with differential should be repeated three months later and then at annual intervals.

CONCLUSION

CHIP must be included in the differential diagnosis of peripheral blood cytopenia. This new entity can help us understand the clinical significance of clonal hematopoiesis.

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

PURPOSES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pretreatment platelet count predicts survival outcome of patients with de novo non-M3 acute myeloid leukemia

Background

Pretreatment platelet count has been reported as a potential tool to predict survival outcome in several solid tumors. However, the predictive value of pretreatment platelet count remains obscure in de novo acute myeloid leukemia (AML) excluding acute promyelocytic leukemia (M3).

Methods

We conducted a retrospective review of 209 patients with de novo non-M3 AML in our institute over a period of 8 years (2007–2015). Receiver operating characteristic (ROC) curve analysis was used to determine the optimal platelet (PLT) cutoff in patients. We analyzed the overall survival (OS) and disease free survival (DFS) using the log-rank test and Cox regression analysis.

Results

By defining the platelet count 50 × 10⁹/L and 120 × 10⁹/L as two cut-off points, we categorized the patients into three groups: low (<50 × 10⁹/L), medium (50–120 × 10⁹/L) and high (>120 × 10⁹/L). On univariate analysis, patients with medium platelet count had longer OS and DFS than those with low or high platelet count. However, the multivariate analysis showed that only longer DFS was observed in patients with medium platelet count than those with low or high platelet count.

Conclusion

Our findings indicate that pretreatment platelet count has a predictive value for the prognosis of patients with non-M3 AML.

Retracted: Influence of genetic variants of IDH1, IDH2, TET2 and DNMT3A on cytarabine cytotoxicity in different populations

'Influence of genetic variants of IDH1, IDH2, TET2 and DNMT3A on cytarabine cytotoxicity in different populations' by Y. Wang & J. K. Lamba1 The above article from the Journal of Clinical Pharmacy and Therapeutics, published online on 21 November 2017 in Wiley Online Library (wileyonlinelibrary.com), has been retracted following discussions with the authors, the Journal Editors and John Wiley & Sons Ltd. The Retraction has been agreed as this paper was submitted under the joint names of Yan Wang, Jatinder K. Lamba and a third co-author. After acceptance of the paper, Dr Wang wrote to the EiC asking for the name of the third co-author to be dropped because of insufficient contribution. The EiC asked that the request be signed by all three authors. When this arrived, the paper was published online with only Dr Wang and Dr Lamba. However, Dr Lamba wrote to the EiC after publication indicating that she had not previously seen the manuscript and that there were co-authors missing. As it is clear that Dr Lamba's signature was forged, we cannot rely on the integrity of the report. The retraction is with the agreement of Dr Lamba but not of Dr Wang. REFERENCE 1. Wang Y, Lamba JK. Influence of genetic variants of IDH1, IDH2, TET2 and DNMT3A on cytarabine cytotoxicity in different populations. J Clin Pharm Ther. 2017;00:1-9. https://doi.org/10.1111/jcpt.12653.

Chronic myelomonocytic leukemia with double-mutations in DNMT3A and FLT3-ITD treated with decitabine and sorafenib

Chronic myelomonocytic leukemia (CMML) is a heterogeneous neoplastic hematologic disorder with worse overall survival. Half of CMML have mutations, but case with concomitant mutations of DNA methyltransferase 3A (DNMT3A) and Internal tandem duplications of the juxtamembrane domain of FLT3 (FLT3-ITD) in CMML was not reported before. We reported a 51-year-old man who had CMML with concomitant mutations in DNMT3A and FLT3-ITD.The patient received decitabine and sorafenib combined treatment. In this report, we reviewed DNMT3A mutation and FLT3 mutation, and we reviewed treatment of decitabine and sorafenib. This report is significant. First: This is the first report on CMML with double-mutations of DNMT3A and FLT3-ITD. Second: It shows the importance of targeted drug in combined treatment of CMML.

DNMT3A (R882) mutation features and prognostic effect in acute myeloid leukemia in Coexistent with NPM1 and FLT3 mutations

OBJECTIVE/BACKGROUND

In the absence of high-risk cytogenetic, DNMT3A (DNA Methyltransferase 3a) mutation status has an impact on outcome in the presence of FLT3 (FMS-like Tyrosine Kinase3) and/or NPM1 (Nucleophosmin). In this study, we focus on the features and effect of DNMT3A (R882) mutation in acute myeloid leukemia (AML) in the presence or absence of NPM1 and FLT3 mutations.

METHODS

A total of 174 cytogenetically normal (CN)-AML cases were analyzed for NPM1, FLT3, and DNMT3A mutations. For NPM1 mutation detection, we used the pyrosequencing technique; for FLT3 mutations, polymerase chain reaction and RFLP with ECO-RV techniques were used, and for DNMT3A mutation analysis, we used Sanger sequencing and RFLP (Restriction Fragment Length Polymorphism) techniques.

RESULTS

NPM1 mutation was found in 40.80%, DNMT3A in 12.06%, and FLT3 mutation was found in 16.66% of 174 CN-AML patients. We also found seven cases which were (NPM1+, FLT3+), 10 cases which were (NPM1+, DNMT3A+), and two cases were found positive for (DNMT3A+, FLT3+) mutations. Adult patients had significantly higher frequency of NPM1 mutation than children (72.22% vs. 16.66%; p = .020), whereas FLT3/ITD and DNMT3A mutation was associated with higher white blood count (p = .081). Immunophenotypically, NPM1 and DNMT3A mutations were significantly associated with the lack of CD34, whereas FLT3/ITD mutation was positively associated with the expression of CD7. We also assessed the overall survival and progression-free survival of DNMT3A mutation status among patients with CN-AML. Indeed, DNMT3A mutations within the CN-AML subset were associated with significantly shorter overall survival and progression-free survival compared to NPM1 and FLT3 mutated patients (p = .067 and p = .065, respectively).

CONCLUSION

DNMT3A R882 mutation plays an important role in CN-AML patients' prognosis and clinical outcomes in the presence and absence of NPM1 and FLT3 mutations.

Cost-effective screening of DNMT3A coding sequence identifies somatic mutation in pediatric T-cell acute lymphoblastic leukemia

BACKGROUND AND OBJECTIVES

In pediatric T-cell acute lymphoblastic leukemia (T-ALL), risk assignment schemes preclude reliable prediction of outcome, and thus, new prognostic factors are needed. Mutations in DNMT3A are candidate prognostic and classification markers in adults with acute myeloid leukemia (AML) and T-ALL and thus were considered as candidates prognostic markers in pediatric T-ALL.

PATIENTS AND METHODS

DNMT3A mutational status was investigated in 74 pediatric T-ALL samples collected at diagnosis. We applied high-resolution melt (HRM) analysis and Sanger sequencing to study the hotspot position (R882) within catalytic MTase domain and exons coding for other functional domains of the protein, known to be mutated in the wide spectrum of hematological malignancies.

RESULTS

We demonstrate a low frequency of mutations in DNMT3A coding sequence in pediatric T-ALL (1.4%, n = 1/74). We identified missense mutation, p.Ala644Thr, which has not been described previously in pediatric T-ALL, but is recurrent in adults with T-ALL and AML.

CONCLUSIONS

Low frequency of DNMT3A mutations in pediatric T-ALL is in striking contrast to adult T-ALL and renders the necessity for the search of other candidate prognostic markers. Combined Sanger sequencing-HRM approach offers a cost-effective option for genotyping DNMT3A coding sequence, with potential clinical application in other hematological malignancies.

MGMT promoter methylation as a potential prognostic marker for acute leukemia

INTRODUCTION

It has been proved that genetic and epigenetic changes play a significant role in the development and progression of acute leukemia. The aim of our study was to evaluate the frequency and prognostic implications of genetic and epigenetic alterations in p15, MGMT, DNMT3A and TP53 genes in acute leukemias.

MATERIAL AND METHODS

We included in the study 59 patients with acute leukemia. Evaluation of TP53 and DNMT3A mutations was performed using sequencing analysis and PCR-RFLP, respectively. Methylation status of MGMT and p15 genes was evaluated using MSP and COBRA, respectively. For assessment of global DNA methylation ELISA-based kit was used.

RESULTS

We found that overall survival was higher for ALL patients. MGMT promoter methylation was significantly associated with patients age at the time of diagnosis (p = 0.03). TP53 and DNMT3A mutations were observed only in AML patients (16.67% and 8.8%, respectively). Patients with acute leukemia and p15 promoter methylation had significantly more frequently mutated TP53 gene (p = 0.04) and AML patients with p15 promoter methylation had significantly more frequently detected global hypomethylation of DNA (p = 0.009). In the group of ALL patients we noted an opposite trend: only patients negative for p15 promoter methylation were characterized by global DNA hypomethylation.

CONCLUSIONS

Our findings demonstrate that MGMT promoter methylation can have a considerable impact on the development of acute leukemia in older patients. DNMT3A and TP53 mutations may play a significant role in AML development. However, further studies conducted in a larger cohort of patients are needed to determine its clinical utility.

Initial Diagnostic Workup of Acute Leukemia: Guideline From the College of American Pathologists and the American Society of Hematology

CONTEXT

- A complete diagnosis of acute leukemia requires knowledge of clinical information combined with morphologic evaluation, immunophenotyping and karyotype analysis, and often, molecular genetic testing. Although many aspects of the workup for acute leukemia are well accepted, few guidelines have addressed the different aspects of the diagnostic evaluation of samples from patients suspected to have acute leukemia.

OBJECTIVE

- To develop a guideline for treating physicians and pathologists involved in the diagnostic and prognostic evaluation of new acute leukemia samples, including acute lymphoblastic leukemia, acute myeloid leukemia, and acute leukemias of ambiguous lineage.

DESIGN

- The College of American Pathologists and the American Society of Hematology convened a panel of experts in hematology and hematopathology to develop recommendations. A systematic evidence review was conducted to address 6 key questions. Recommendations were derived from strength of evidence, feedback received during the public comment period, and expert panel consensus.

RESULTS

- Twenty-seven guideline statements were established, which ranged from recommendations on what clinical and laboratory information should be available as part of the diagnostic and prognostic evaluation of acute leukemia samples to what types of testing should be performed routinely, with recommendations on where such testing should be performed and how the results should be reported.

CONCLUSIONS

- The guideline provides a framework for the multiple steps, including laboratory testing, in the evaluation of acute leukemia samples. Some aspects of the guideline, especially molecular genetic testing in acute leukemia, are rapidly changing with new supportive literature, which will require on-going updates for the guideline to remain relevant.

The spectrum of DNMT3A variants in Tatton-Brown-Rahman syndrome overlaps with that in hematologic malignancies

De novo, germline variants in DNMT3A cause Tatton-Brown-Rahman syndrome (TBRS). This condition is characterized by overgrowth, distinctive facial appearance, and intellectual disability. Somatic DNMT3A variants frequently occur in hematologic malignances, particularly acute myeloid leukemia. The Arg882 residue is the most common site of somatic DNMT3A variants, and has also been altered in patients with TBRS. Here we present three additional patients with this disorder attributed to DNMT3A germline variants that disrupt the Arg882 codon, suggesting that this codon may be a germline mutation hotspot in this disorder. Furthermore, based on the investigation of previously reported variants in patients with TBRS, we found overlap in the spectrum of DNMT3A variants observed in this disorder and somatic variants in hematological malignancies.

DNMT3A mutations in Chinese childhood acute myeloid leukemia

BACKGROUND

DNA methyltransferase 3A (DNMT3A) mutations have been found in approximately 20% of adult acute myeloid leukemia (AML) patients and in 0% to 1.4% of children with AML, and the hotspots of mutations are mainly located in the catalytic methyltransferase domain, hereinto, mutation R882 accounts for 60%. Although the negative effect of DNMT3A on treatment outcome is well known, the prognostic significance of other DNMT3A mutations in AML is still unclear. Here, we tried to determine the incidence and prognostic significance of DNMT3A mutations in a large cohort in Chinese childhood AML.

METHODS

We detected the mutations in DNMT3A exon 23 by polymerase chain reaction and direct sequencing in 342 children with AML (0-16 years old) from January 2005 to June 2013, treated on BCH-2003 AML protocol. The correlation of DNMT3A mutations with clinical characteristics, fusion genes, other molecular anomalies (FLT3 internal tandem duplication [FLT3-ITD], Nucleophosmin 1, C-KIT (KIT proto-oncogene receptor tyrosine kinase), and Wilms tumor 1 mutations), and treatment outcome were analyzed.

RESULTS

DNMT3A mutations were detected in 4 out of 342 (1.2%) patients. Two patients were PML-RARA positive and 1 patient was FLT3-ITD positive. The mutations in coding sequences included S892S, V912A, R885G, and Q886R. Furthermore, there was 1 intronic mutation (c.2739+55A>C) found in 1 patient. No association of DNMT3A mutations with common clinical features was found. Two patients with DNMT3A mutations died of relapse or complications during treatment. One patient gave up treatment due to remission induction failure in day 33. Only 1 patient achieved continuous complete remission.

CONCLUSIONS

DNMT3A mutations were rare in Chinese children with AML including PML-RARA positive APL. The mutation positions were different from the hotspots reported in adult AML. DNMT3A mutations may have adverse impact on prognosis of children with AML.

Immunological effects of hypomethylating agents

INTRODUCTION

Epigenetic changes resulting from aberrant methylation patterns are a recurrent observation in hematologic malignancies. Hypomethylating agents have a well-established role in the management of patients with high-risk myelodysplastic syndrome or acute myeloid leukemia. In addition to the direct effects of hypomethylating agents on cancer cells, there are several lines of evidence indicating a role for immune-mediated anti-tumor benefits from hypomethylating therapy. Areas covered: We reviewed the clinical and basic science literature for the effects of hypomethylating agents, including the most commonly utilized therapeutics azacitidine and decitabine, on immune cell subsets. We summarized the effects of hypomethylating agents on the frequency and function of natural killer cells, T cells, and dendritic cells. In particular, we highlight the effects of hypomethylating agents on expression of immune checkpoint inhibitors, leukemia-associated antigens, and endogenous retroviral elements. Expert commentary: In vitro and ex vivo studies indicate mixed effects on the function of natural killer, dendritic cells and T cells following treatment with hypomethylating agents. Clinical correlates of immune function have suggested that hypomethylating agents have immunomodulatory functions with the potential to synergize with immune checkpoint therapy for the treatment of hematologic malignancy, and has become an active area of clinical research.

DNMT3A mutant transcript levels persist in remission and do not predict outcome in patients with acute myeloid leukemia

We investigated the prognostic impact of minimal residual disease (MRD) monitoring in acute myeloid leukemia patients harboring DNA methyltransferase 3A-R882H/-R882C mutations (DNMT3A^mut). MRD was determined by real-time quantitative PCR (RQ-PCR) in 1494 samples of 181 DNMT3A^mut patients. At the time of diagnosis, DNMT3A^mut transcript levels did not correlate with presenting clinical characteristics and concurrent gene mutations as well as the survival end points. In Cox regression analyses, bone marrow (BM) DNMT3A^mut transcript levels (log10-transformed continuous variable) were not associated with the rate of relapse or death. DNMT3A^mut transcript levels were significantly higher in BM than in blood after induction I (P=0.01), induction II (P=0.05), consolidation I (P=0.004) and consolidation II (P=0.008). With regard to the clinically relevant MRD time points, after two cycles of induction and at the end of therapy, DNMT3A^mut transcript levels had no impact on the end point remission duration and overall survival. Of note, only a minority of the patients achieved RQ-PCR negativity, whereas most had constantly high DNMT3A^mut transcript levels, a finding which is consistent with the persistence of clonal hematopoiesis in hematological remission.

Conditional knockin of Dnmt3a R878H initiates acute myeloid leukemia with mTOR pathway involvement

DNMT3A is frequently mutated in acute myeloid leukemia (AML). To explore the features of human AML with the hotspot DNMT3A R882H mutation, we generated Dnmt3a R878H conditional knockin mice, which developed AML with enlarged Lin^-Sca1⁺cKit⁺ cell compartments. The transcriptome and DNA methylation profiling of bulk leukemic cells and the single-cell RNA sequencing of leukemic stem/progenitor cells revealed significant changes in gene expression and epigenetic regulatory patterns that cause differentiation arrest and growth advantage. Consistent with leukemic cell accumulation in G₂/M phase, CDK1 was up-regulated due to mTOR activation associated with DNA hypomethylation. Overexpressed CDK1-mediated EZH2 phosphorylation resulted in an abnormal trimethylation of H3K27 profile. The mTOR inhibitor rapamycin elicited a significant therapeutic response in Dnmt3a^R878H/WT mice.