Acute megakaryoblastic leukemia with acquired trisomy 21 and GATA1 mutations in phenotypically normal children

Single-cell transcriptomics reveal synergistic and antagonistic effects of T21 and GATA1s on hematopoiesis

Trisomy 21 (T21), or Down syndrome (DS), is associated with baseline macrocytic erythrocytosis, thrombocytopenia, and neutrophilia, and transient abnormal myelopoiesis (TAM) and myeloid leukemia of DS (ML-DS). TAM and ML-DS blasts both arise from an aberrant megakaryocyte-erythroid progenitor and exclusively express GATA1s, the truncated isoform of GATA1 , while germline GATA1s mutations in a non-T21 context lead to congenital cytopenias without a leukemic predisposition. This suggests that T21 and GATA1s perturb hematopoiesis independently and synergistically, but this interaction has been challenging to study in part due to limited human cell and murine models. To dissect the developmental impacts of GATA1s on hematopoiesis in euploid and T21 cells, we performed a single-cell RNA-sequencing timecourse on hematopoietic progenitors (HPCs) derived from isogenic human induced pluripotent stem cells differing only by chromosome 21 and/or GATA1 status. These HPCs were surprisingly heterogeneous and displayed spontaneous lineage skew apparently dictated by T21 and/or GATA1s. In euploid cells, GATA1s nearly eliminated erythropoiesis, impaired MK maturation, and promoted an immature myelopoiesis, while in T21 cells, GATA1s appeared to compete with the enhanced erythropoiesis and suppressed megakaryopoiesis driven by T21 to give rise to immature erythrocytes, MKs, and myeloid cells. T21 and GATA1s both disrupted temporal regulation of lineage-specific transcriptional programs and specifically perturbed cell cycle genes. These findings in an isogenic system can thus be attributed specifically to T21 and GATA1s and suggest that these genetic changes together enhance HPC proliferation at the expense of maturation, consistent with a pro-leukemic phenotype.

Analysis 33 patients of non-DS-AMKL with or without acquired trisomy 21 from multiple centers and compared to 118 AML patients

BACKGROUND

Acute megakaryoblastic leukemia (AMKL) without Down syndrome (non-DS-AMKL) usually a worse outcome than DS-AMKL. Acquired trisomy 21(+21) was one of the most common cytogenetic abnormalities in non-DS-AMKL. Knowledge of the difference in the clinical characteristics and prognosis between non-DS-AMKL with +21 and those without +21 is limited.

OBJECTIVE

Verify the clinical characteristics and prognosis of non-DS-AMKL with +21.

METHOD

We retrospectively analyzed 33 non-DS-AMKL pediatric patients and 118 other types of AML, along with their clinical manifestations, laboratory data, and treatment response.

RESULTS

Compared with AMKL without +21, AMKL with +21 has a lower platelet count (44.04 ± 5.01G/L) at onset (P > 0.05). Differences in remission rates between AMKL and other types of AML were not significant. Acquired trisomy 8 in AMKL was negatively correlated with the long-term OS rate (P < 0.05), while +21 may not be an impact factor. Compared with the other types of AML, AMKL has a younger onset age (P < 0.05), with a mean of 22.27 months. Anemia, hemorrhage, lymph node enlargement, lower white blood cell, and complex karyotype were more common in AMKL (P < 0.05). AMKL has a longer time interval between onset to diagnosis (53.61 ± 71.15 days) (P < 0.05), and patients with a diagnosis delay ≥3 months always presented as thrombocytopenia or pancytopenia initially.

CONCLUSIONS

Due to high heterogeneity, high misdiagnosis rate, and myelofibrosis, parts of AMKL may take a long time to be diagnosed, requiring repeated bone marrow punctures. Complex karyotype was common in AMKL. +21 may not be a promising indicator of a poor prognosis.

Congenital leukemia: A case report and review of literature

BACKGROUND

Acute leukemia in newborns is also known as neonatal or congenital leukemia (CL) and is a rare disease with an incidence rate of 1-5 per 1000000 live births. After birth, infants with CL exhibit infiltrative cutaneous nodules, hepatosplenomegaly, thrombocytopenia, and immature leukocytes in the peripheral blood. These symptoms are frequently accompanied by congenital abnormalities including trisomy 21, trisomy 9, trisomy 13, or Turner syndrome. Despite significant advances in disease management, the survival rate is approximately 25% at 2 years.

CASE SUMMARY

Here, we document a case of trisomy 21-related acute myeloid leukemia (AML) in a female neonate. The baby was sent to the neonatal intensive care unit because of anorexia, poor responsiveness, and respiratory distress. She was diagnosed with AML based on bone marrow aspiration and immunophenotyping. Genetic sequencing identified a mutation in the GATA1 gene. After receiving the diagnosis, the parents decided against medical care for their child, and the baby died at home on day 9 after birth.

CONCLUSIONS

The newborn infant was diagnosed with trisomy 21-related AML. Genetic sequencing identified a mutation in the GATA1 gene. The parents abandoned medical treatment for their infant after receiving the diagnosis, and the infant died at home on the 9th day after birth.

Low-Level Germline 48,XYY,+21 Mosaicism Associated with Transient Abnormal Myelopoiesis in a Phenotypically Normal Neonate

Transient abnormal myelopoiesis (TAM) is a unique neonatal leukemoid reaction caused by a pathognomonic GATA1 mutation in conjunction with the gene dosage effect of trisomy 21, which is either of germline or somatic origin. We encountered a 48,XYY,+21 phenotypically normal neonate with Down syndrome who developed TAM due to cryptic germline mosaicism. Quantification of the mosaic ratio was complicated by an overestimation bias of hyperproliferating TAM within the germline component. To establish a workflow for such a clinical scenario, we analyzed the cytogenetic findings of neonates with TAM associated with somatic or low-level germline mosaicism. We showed that multistep diagnostic procedures (i.e., paired cytogenetic analyses of peripheral blood specimens in culture with or without phytohemagglutinin; serial cytogenetic studies of more than one tissue, such as the buccal membrane; and complementary DNA-based GATA1 mutation screening) can verify the specificity of cytogenetic testing for phenotypically normal neonates with TAM suspected of mosaicism.

Bullous eruptions in transient abnormal myelopoiesis with normal phenotype

Cutaneous lesions are common manifestation of congenital leukaemia especially myeloid type with incidence of 25%-50% in reported cases. It is relatively rare in transient abnormal myelopoiesis (TAM) seen in trisomy 21 (~10%). The rashes seen in leukaemia and TAM are different. We report a case with a rare presentation of confluent bullous eruption in a phenotypically normal neonate with trisomy 21 restricted to haematopoietic blast cells. This rash resolved rapidly after low-dose cytarabine therapy with normalisation of total white cell counts. The risk of Down syndrome-associated myeloid leukaemia in such cases is still high (19%-23%) in first 5 years and rare thereafter.

Advances in molecular characterization of myeloid proliferations associated with Down syndrome

Myeloid leukemia associated with Down syndrome (ML-DS) has a unique molecular landscape that differs from other subtypes of acute myeloid leukemia. ML-DS is often preceded by a myeloproliferative neoplastic condition called transient abnormal myelopoiesis (TAM) that disrupts megakaryocytic and erythroid differentiation. Over the last two decades, many genetic and epigenetic changes in TAM and ML-DS have been elucidated. These include overexpression of molecules and micro-RNAs located on chromosome 21, GATA1 mutations, and a range of other somatic mutations and chromosomal alterations. In this review, we summarize molecular changes reported in TAM and ML-DS and provide a comprehensive discussion of these findings. Recent advances in the development of CRISPR/Cas9-modified induced pluripotent stem cell-based disease models are also highlighted. However, despite significant progress in this area, we still do not fully understand the pathogenesis of ML-DS, and there are no targeted therapies. Initial diagnosis of ML-DS has a favorable prognosis, but refractory and relapsed disease can be difficult to treat; therapeutic options are limited in Down syndrome children by their stronger sensitivity to the toxic effects of chemotherapy. Because of the rarity of TAM and ML-DS, large-scale multi-center studies would be helpful to advance molecular characterization of these diseases at different stages of development and progression.

Germline GATA1s generating mutations predispose to leukemia with acquired trisomy 21 and Down syndrome-like phenotype

Individuals with Down syndrome are at increased risk of myeloid leukemia in early childhood associated with acquisition of GATA1 mutations that generate a short GATA1 isoform called GATA1s. Germline GATA1s generating mutations result in congenital anemia in males. We report on two unrelated families harboring germline GATA1s generating mutations in which several members developed acute megakaryoblastic leukemia in early childhood. All evaluable leukemias had acquired trisomy or tetrasomy 21. The leukemia characteristics overlapped those of myeloid leukemia of Down syndrome including age of onset of less than 4 years, unique immunophenotype, complex karyotype, gene expression pattern, and drug sensitivity. These findings demonstrate that the combination of trisomy 21 and GATA1s generating mutations results in a unique myeloid leukemia independent of whether the GATA1 mutation or trisomy 21 is the primary or secondary event and suggest that there is unique functional cooperatively between GATA1s and trisomy 21 in leukemogenesis. The family histories also indicate that germline GATA1s generating mutations should be included among those associated with familial myelodysplastic syndrome and leukemia predisposition.

GATA1 mutation analysis and molecular landscape characterization in acute myeloid leukemia with trisomy 21 in pediatric patients

INTRODUCTION

Accurate detection of GATA1 mutation is highly significant in patients with acute myeloid leukemia (AML) and trisomy 21 as it allows optimization of clinical protocol. This study was aimed at (a) enhanced search for GATA1 mutations; and (b) characterization of molecular landscapes for such conditions.

METHODS

The DNA samples from 44 patients with newly diagnosed de novo AML with trisomy 21 were examined by fragment analysis and Sanger sequencing of the GATA1 exon 2, complemented by targeted high-throughput sequencing (HTS).

RESULTS

Acquired GATA1 mutations were identified in 43 cases (98%). Additional mutations in the genes of JAK/STAT signaling, cohesin complex, and RAS pathway activation were revealed by HTS in 48%, 36%, and 16% of the cases, respectively.

CONCLUSIONS

The GATA1 mutations were reliably determined by fragment analysis and/or Sanger sequencing in a single PCR amplicon manner. For patients with extremely low blast counts and/or rare variants, the rapid screening with simple molecular approaches must be complemented with HTS. The JAK/STAT and RAS pathway-activating mutations may represent an extra option of targeted therapy with kinase inhibitors.

Gain of chromosome 21 in hematological malignancies: lessons from studying leukemia in children with Down syndrome

Structural and numerical alterations of chromosome 21 are extremely common in hematological malignancies. While the functional impact of chimeric transcripts from fused chromosome 21 genes such as TEL-AML1, AML1-ETO, or FUS-ERG have been extensively studied, the role of gain of chromosome 21 remains largely unknown. Gain of chromosome 21 is a frequently occurring aberration in several types of acute leukemia and can be found in up to 35% of cases. Children with Down syndrome (DS), who harbor constitutive trisomy 21, highlight the link between gain of chromosome 21 and leukemogenesis, with an increased risk of developing acute leukemia compared with other children. Clinical outcomes for DS-associated leukemia have improved over the years through the development of uniform treatment protocols facilitated by international cooperative groups. The genetic landscape has also recently been characterized, providing an insight into the molecular pathogenesis underlying DS-associated leukemia. These studies emphasize the key role of trisomy 21 in priming a developmental stage and cellular context susceptible to transformation, and have unveiled its cooperative function with additional genetic events that occur during leukemia progression. Here, using DS-leukemia as a paradigm, we aim to integrate our current understanding of the role of trisomy 21, of critical dosage-sensitive chromosome 21 genes, and of associated mechanisms underlying the development of hematological malignancies. This review will pave the way for future investigations on the broad impact of gain of chromosome 21 in hematological cancer, with a view to discovering new vulnerabilities and develop novel targeted therapies to improve long term outcomes for DS and non-DS patients.

Clinical Characteristics and Prognosis of 27 Patients with Childhood Acute Megakaryoblastic Leukemia

Background

The aim of this study was to investigate the clinical features and prognostic factors of childhood acute megakaryoblastic leukemia (AMKL).

Material/Methods

The data of 27 cases of childhood AMKL admitted from November 2009 to July 2018 were retrospectively analyzed. The survival analysis and prognostic factors were analyzed by Kaplan-Meier method.

Results

The median follow-up time was 26.4 months in 27 cases, and the complete response rate was 92.31% after 2 chemotherapy courses. Eight patients underwent bone marrow transplantation after 3–6 courses. Five patients died after transplantation, 4 of whom died due to recurrence after transplantation. Of the 27 patients, 10 developed recurrence (37.04%), and 8/10 had recurrence within 1 year. The 3-year overall survival rate and disease-free survival rates were (47±12)% and (36±14)%, respectively. Of the 27 AMKL cases, the 3 with Down syndrome (DS-AMKL) all survived after treatment, and the 3-year overall survival rate was 100%. However, of the other 24 AMKL patients without Down syndrome (non-DS-AMKL), 6 died and 6 abandoned treatment, and the 3-year overall survival rate was only 50%. Univariate analysis showed that 3-year overall survival rate was not correlated to gender, age, number of newly diagnosed white blood cells, karyotype, remission after 2 courses of treatment, and transplant after 3 courses of treatment of childhood AMKL cases. Nevertheless, recurrence and remission after 2 courses of treatment were significantly correlated with 3-year overall survival rate.

Conclusions

Children with non-DS-AMKL have a high degree of malignancy and are prone to early recurrence with a poor prognosis, whereas the prognosis of DS-AMKL is relatively good. Recurrence after treatment and remission after 2 courses of treatment are important factors influencing the prognosis of childhood AMKL. Recurrence after transplantation is the leading cause of death in transplantation patients.

Clinical, cytogenetic, and molecular analyses of 17 neonates with transient abnormal myelopoiesis and nonconstitutional trisomy 21

BACKGROUND

Transient abnormal myelopoiesis (TAM) is a unique myeloproliferative disorder that occurs in neonates with constitutional trisomy 21/Down syndrome (DS). Although TAM also develops in neonates without constitutional trisomy 21, the clinical, cytogenetic, and molecular characteristics of those patients are not fully understood.

PROCEDURE

We retrospectively evaluated the clinical and cytogenetic findings and GATA1 mutation status of 17 neonates with TAM and nonconstitutional trisomy 21 tested for GATA1 mutations at our institute, and compared the findings with those of 64 neonates with TAM and constitutional trisomy 21/DS.

RESULTS

DS clinical features were observed in five of the 17 (29%) patients. In all patients, both trisomy 21 and GATA1 mutations were detected in diagnostic samples. Over a median follow-up of 33 (range, 0-139) months, early death (< 6 months of age) occurred in four patients (24%). Overall and event-free survivals were not significantly different between the patients with TAM and nonconstitutional trisomy 21 and those with TAM and constitutional trisomy 21/DS (five-year overall survival: 76% ± 10% vs 53% ± 13%, P = 0.40; five-year event-free survival: 55% ± 13% vs 48% ± 12%, P = 0.90). The five-year cumulative incidence of progression to myeloid leukemia of DS was also similar between the groups (21% vs 24%, P = 0.80).

CONCLUSIONS

Patients with TAM and nonconstitutional trisomy 21 exhibited similar biology and outcomes to those with TAM and constitutional trisomy 21/DS. The possibility of TAM should be considered even in phenotypically normal neonates with TAM symptoms, for appropriate management.

Molecular features, prognosis, and novel treatment options for pediatric acute megakaryoblastic leukemia

INTRODUCTION

Acute megakaryoblastic leukemia (AMegL) is a rare hematological neoplasm most often diagnosed in children and is commonly associated with Down's syndrome (DS). Although AMegLs are specifically characterized and typically diagnosed by megakaryoblastic expansion, recent advancements in molecular analysis have highlighted the heterogeneity of this disease, with specific cytogenic and genetic alterations characterizing different disease subtypes. Areas covered: This review will focus on describing recurrent molecular variations in both DS and non-DS pediatric AMegL, their role in promoting leukemogenesis, their association with different clinical aspects and prognosis, and finally, their influence on future treatment strategies with a number of specific drugs beyond conventional chemotherapy already under development. Expert opinion: Deep understanding of the genetic and molecular landscape of AMegL will lead to better and more precise disease classification in terms of diagnosis, prognosis, and possible targeted therapies. Development of new therapeutic approaches based on these molecular characteristics will hopefully improve AMegL patient outcomes.

Acute megakaryoblastic leukemia (excluding Down syndrome) remains an acute myeloid subgroup with inferior outcome in the French ELAM02 trial

We report the outcome of 27 children with de novo acute megakaryoblastic leukemia (AMKL) (excluding Down syndrome) enrolled in the French multicenter prospective study ELAM02 (2005-2011). There was no difference in gender, initial leukocyte count, CNS involvement, and complete remission rate (88.9%), as compared to other acute myeloid leukemia (AML) subtypes. AMKL patients had a significantly poorer outcome (5-year overall survival 54% [CI 95% 33%-71%] than children with other AML subtypes (5-year overall survival 73% [CI 95% 68%-77%] p = 0.02). Gender, age, CNS leukemia, hyperleukocytosis, complete remission or cytogenetic subgroups were not significant prognostic factors of disease-free survival. AMKL (excluding Down syndrom) remains an AML subgroup with inferior outcome.

Sometimes it is better to wait: First Italian case of a newborn with transient abnormal myelopoiesis and a favorable prognosis

Congenital leukemia is rare disease with an incidence of one to five cases per million births. Transient abnormal myelopoiesis (TAM), also called transient myeloproliferative disorder, is a pre-leukemia disorder that may occur in Down syndrome (DS) or non-DS infants. TAM may enter spontaneous remission; however, continual monitoring is required, as this disorder has been observed to develop into acute megakaryoblastic leukemia in 16–30% of cases. In the literature, 16 cases of TAM in non-DS infants have been reported. The case presented in the current study is, to the best of our knowledge, the first case of an Italian non-DS newborn presenting with clinical manifestations of acute leukemia at five days after birth, exhibiting a normal karyotype, trisomy 21 only in blast cells, and spontaneous remission. Chromosomal analyses on peripheral blood cells, bone marrow cells and dermal fibroblasts were conducted using a G-banding technique, and fluorescence in situ hybridization (FISH) was used to identify the critical regions of DS. Amplification of GATA binding protein 1 (GATA1) exon 2 genomic DNA was performed using polymerase chain reaction. Cytogenetic analysis of 50 peripheral blood cells and dermal fibroblasts from the patient revealed a normal karyotype: 46, XX. Conversely, cytogenetic analysis of the patient's bone marrow revealed an abnormal karyotype 47, XX+21. In order to investigate this result, FISH was performed, which identified the presence of three signals in 70% of the cells and two signals in 30% of bone marrow cells. GATA1 sequencing revealed the substitution of a single base (c.150delG) in exon 2. Seven months after the initial analysis, FISH and cytogenetic analyses of the stimulated/unstimulated peripheral blood cells and bone marrow cells were performed, revealing that each exhibited diploid signals, as observed in a normal karyotype.

Recurrent abnormalities can be used for risk group stratification in pediatric AMKL: a retrospective intergroup study

Genetic abnormalities and early treatment response are the main prognostic factors in acute myeloid leukemia (AML). Acute megakaryoblastic leukemia (AMKL) is a rare subtype of AML. Deep sequencing has identified CBFA2T3/GLIS2 and NUP98/KDM5A as recurrent aberrations, occurring in similar frequencies as RBM15/MKL1 and KMT2A-rearrangements. We studied whether these cytogenetic aberrations can be used for risk group stratification. To assess frequencies and outcome parameters of recurrent cytogenetic aberrations in AMKL, samples and clinical data of patients treated by the Associazione Italiana Ematologia Oncologia Pediatrica, Berlin-Frankfurt-Munster Study Group, Children's Oncology Group, Dutch Childhood Oncology Group, and the Saint Louis Hôpital were collected, enabling us to screen 153 newly diagnosed pediatric AMKL cases for the aforementioned aberrations and to study their clinical characteristics and outcome. CBFA2T3/GLIS2 was identified in 16% of the cases; RBM15/MKL1, in 12%; NUP98/KDM5A and KMT2A rearrangements, in 9% each; and monosomy 7, in 6%. These aberrations were mutually exclusive. RBM15/MKL1-rearranged patients were significantly younger. No significant differences in sex and white blood cell count were found. NUP98/KDM5A, CBFA2T3/GLIS2, KMT2A-rearranged lesions and monosomy 7 (NCK-7) independently predicted a poor outcome, compared with RBM15/MKL1-rearranged patients and those with AMKL not carrying these molecular lesions. NCK-7-patients (n = 61) showed a 4-year probability of overall survival of 35 ± 6% vs 70 ± 5% in the RBM15/MKL1-other groups (n = 92, P < .0001) and 4-year probability of event-free survival of 33 ± 6% vs 62 ± 5% (P = .0013), the 4-year cumulative incidence of relapse being 42 ± 7% and 19 ± 4% (P = .003), respectively. We conclude that these genetic aberrations may be used for risk group stratification of pediatric AMKL and for treatment tailoring.