Long-term follow-up of haploidentical haematopoietic stem cell transplantation in paediatric patients with high-risk acute myeloid leukaemia: Report from a single centre.

Data from 200 children with high-risk acute myeloid leukaemia who underwent their first haploidentical haematopoietic stem cell transplantation (haplo-HSCT) between 2015 and 2021 at our institution were analysed. The 4-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) were 71.9%, 62.3% and 32.4% respectively. The 100-day cumulative incidences of grade II-IV and III-IV acute graft-versus-host disease (aGVHD) were 41.1% and 9.5% respectively. The 4-year cumulative incidence of chronic GVHD (cGVHD) was 56.1%, and that of moderate-to-severe cGVHD was 27.3%. Minimal residual disease (MRD)-positive (MRD+) status pre-HSCT was significantly associated with lower survival and a higher risk of relapse. The 4-year OS, EFS and CIR differed significantly between patients with MRD+ pre-HSCT (n = 97; 63.4%, 51.4% and 41.0% respectively) and those with MRD-negative (MRD-) pre-HSCT (n = 103; 80.5%, 73.3% and 23.8% respectively). Multivariate analysis also revealed that acute megakaryoblastic leukaemia without Down syndrome (non-DS-AMKL) was associated with extremely poor outcomes (hazard ratios and 95% CIs for OS, EFS and CIR: 3.110 (1.430-6.763), 3.145 (1.628-6.074) and 3.250 (1.529-6.910) respectively; p-values were 0.004, 0.001 and 0.002 respectively). Thus, haplo-HSCT can be a therapy option for these patients, and MRD status pre-HSCT significantly affects the outcomes. As patients with non-DS-AMKL have extremely poor outcomes, even with haplo-HSCT, a combination of novel therapies is urgently needed.

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, which is 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 2 unrelated families that harbor germline GATA1s-generating mutations in which several members developed acute megakaryoblastic leukemia in early childhood. All evaluable leukemias had acquired trisomy 21 or tetrasomy 21. The leukemia characteristics overlapped with those of myeloid leukemia associated with Down syndrome, including age of onset at younger than 4 years, unique immunophenotype, complex karyotype, gene expression patterns, 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 a unique functional cooperation 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 predisposition for myelodysplastic syndrome and leukemia.

t(1;22)(p13;q13) Acute Megakaryoblastic Leukemia Complicated by Hepatic Fibrosis: Antifibrosis Therapy?

BACKGROUND: There is no established effective treatment for patients with t(1;22)(p13;q13) acute megakaryoblastic leukemia (AMKL) and hepatic fibrosis. OBSERVATION: Here we report the outcomes of 2 t(1;22)(p13;q13) AMKL patients with hepatic fibrosis. One patient died from liver failure despite the control of leukemia. The other patient was successfully treated with reduced-intensity chemotherapy and antifibrosis therapy with tretinoin and α-tocopheryl acetate, the hepatic fibrosis resolved and leukemia was in remission for 3 years. CONCLUSIONS: Reduced-intensity chemotherapy plus antifibrosis therapy with tretinoin and α-tocopheryl acetate could be a treatment option for these patients with t(1;22)(p13;q13) AMKL and hepatic fibrosis.

Highly sensitive detection of GATA1 mutations in patients with myeloid leukemia associated with Down syndrome by combining Sanger and targeted next generation sequencing.

Myeloid leukemia associated with Down syndrome (ML-DS) is characterized by a predominance of acute megakaryoblastic leukemia, the presence of GATA1 mutations and a favorable outcome. Because DS children can also develop conventional acute myeloid leukemia with unfavorable outcome, detection of GATA1 mutations is important for diagnosis of ML-DS. However, myelofibrosis and the significant frequency of dry taps have hampered practical screening of GATA1 mutations using bone marrow (BM) samples. In response to those problems, 82 patients were enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-D11 study. GATA1 mutations were analyzed by Sanger sequencing (SS) using genomic DNA (gDNA) from BM and cDNA from peripheral blood (PB) followed by targeted next-generation sequencing (NGS) using pooled diagnostic samples. BM and PB samples were obtained from 71 (87%) and 82 (100%) patients, respectively. GATA1 mutations were detected in 46 (56%) and 58 (71%) patients by SS using BM gDNA and PB cDNA, respectively. Collectively, GATA1 mutations were identified in 73/82 (89%) patients by SS. Targeted NGS detected GATA1 mutations in 74/82 (90%) patients. Finally, combining the results of SS with those of targeted NGS, GATA1 mutations were identified in 80/82 (98%) patients. These results indicate that SS using BM gDNA and PB cDNA is a rapid and useful method for screening for GATA1 mutations in ML-DS patients. Thus, a combination of SS and targeted NGS is a sensitive and useful method to evaluate the actual incidence and clinical significance of GATA1 mutations in ML-DS patients.

Mediastinal Germ Cell Tumor and Acute Megakaryoblastic Leukemia With Co-occurring KRAS Mutation and Complex Cytogenetics.

Young males have a unique but rare predilection to develop mediastinal nonseminomatous germ cell tumors (NSGCTs) and concomitant acute megakaryoblastic leukemia (AMKL). Common cytogenetic and molecular abnormalities such as isochromosome 12p and somatic Tumor Protein P53(TP53) and Phosphatase And Tensin Homolog (PTEN) mutations have been reported in the presumed mutual neoplastic clones of origin. We report the case of a 17-year-old male who presented with a mediastinal NSGCT with high-grade sarcomatous transformation and a diagnosis of AMKL approximately 4 months later. Next-generation sequencing revealed identical KRAS Proto-Oncogene, GTPase (KRAS) p.Ala146Thr, TP53 p.Leu257Pro, and PTEN p.Leu181Pro missense mutations at similar variant allele frequencies in both the NSGCT and AMKL samples. Cytogenetic and microarray analyses detected shared copy gains in all chromosomes except chromosomes 9, 13, and Y. Multiple additional clonal chromosomal alterations were detected in the AMKL sample when compared with the NSGCT. This case emphasizes the shared clonal origins of these malignancies and identifies KRAS and other copy number alterations as potential molecular drivers in a subset of these combined diseases.

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 AND 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.

Late mortality and morbidity among long-term leukemia survivors with Down syndrome: A nationwide population-based cohort study.

BACKGROUND: Late health consequences of treatment for childhood leukemia are well documented. Although individuals with Down syndrome (DS) have a substantially increased risk of leukemia, information on late effects in this group is almost nonexistent. The aim of this study was to evaluate the mortality and morbidity among 5-year leukemia survivors with DS. PROCEDURE: We compared 5-year leukemia survivors with leukemia-free individuals with DS. All individuals born with DS in Denmark between 1960 and 2007 and in Sweden between 1973 and 2009 were included. Long-term morbidity was estimated by comparing hospitalization rates between survivors and leukemia-free individuals. RESULTS: In total, we found 6,705 individuals with DS, 84 of whom were 5-year survivors of leukemia. Survivors had a higher risk of death (hazard ratio [HR] 5.9; 95% confidence interval [CI]: 2.7-13) compared with leukemia-free individuals. All deaths (n = 7) among 5-year leukemia survivors were due to relapse. Survivors had a higher hospitalization rate (HR 4.4; 95% CI: 3.1-6.2). However, most of these hospitalizations were due to relapse. Censoring individuals who either had a relapse or were being treated for a relapse more than 5 years from the initial diagnosis (n = 9) attenuated the association (HR 1.4; 95% CI: 1.0-2.1). CONCLUSION: In this study, we found that relapse was the main reason for death and hospitalization among leukemia survivors with DS, and not late effects. These results are reassuring for individuals treated for DS associated with leukemia and their parents.

miR-125b-2 is a potential oncomiR on human chromosome 21 in megakaryoblastic leukemia.

Children with trisomy 21/Down syndrome (DS) are at high risk to develop acute megakaryoblastic leukemia (DS-AMKL) and the related transient leukemia (DS-TL). The factors on human chromosome 21 (Hsa21) that confer this predisposing effect, especially in synergy with consistently mutated transcription factor GATA1 (GATA1s), remain poorly understood. Here, we investigated the role of Hsa21-encoded miR-125b-2, a microRNA (miRNA) overexpressed in DS-AMKL/TL, in hematopoiesis and leukemogenesis. We identified a function of miR-125b-2 in increasing proliferation and self-renewal of human and mouse megakaryocytic progenitors (MPs) and megakaryocytic/erythroid progenitors (MEPs). miR-125b-2 overexpression did not affect megakaryocytic and erythroid differentiation, but severely perturbed myeloid differentiation. The proproliferative effect of miR-125b-2 on MEPs accentuated the Gata1s mutation, whereas growth of DS-AMKL/TL cells was impaired upon miR-125b repression, suggesting synergism during leukemic transformation in GATA1s-mutated DS-AMKL/TL. Integrative transcriptome analysis of hematopoietic cells upon modulation of miR-125b expression levels uncovered a set of miR-125b target genes, including DICER1 and ST18 as direct targets. Gene Set Enrichment Analysis revealed that this target gene set is down-regulated in DS-AMKL patients highly expressing miR-125b. Thus, we propose miR-125b-2 as a positive regulator of megakaryopoiesis and an oncomiR involved in the pathogenesis of trisomy 21-associated megakaryoblastic leukemia.

Exome sequencing identifies putative drivers of progression of transient myeloproliferative disorder to AMKL in infants with Down syndrome.

Some neonates with Down syndrome (DS) are diagnosed with self-regressing transient myeloproliferative disorder (TMD), and 20% to 30% of those progress to acute megakaryoblastic leukemia (AMKL). We performed exome sequencing in 7 TMD/AMKL cases and copy-number analysis in these and 10 additional cases. All TMD/AMKL samples contained GATA1 mutations. No exome-sequenced TMD/AMKL sample had other recurrently mutated genes. However, 2 of 5 TMD cases, and all AMKL cases, showed mutations/deletions other than GATA1, in genes proven as transformation drivers in non-DS leukemia (EZH2, APC, FLT3, JAK1, PARK2-PACRG, EXT1, DLEC1, and SMC3). One patient at the TMD stage revealed 2 clonal expansions with different GATA1 mutations, of which 1 clone had an additional driver mutation. Interestingly, it was the other clone that gave rise to AMKL after accumulating mutations in 7 other genes. Data suggest that GATA1 mutations alone are sufficient for clonal expansions, and additional driver mutations at the TMD stage do not necessarily predict AMKL progression. Later in infancy, leukemic progression requires "third-hit driver" mutations/somatic copy-number alterations found in non-DS leukemias. Putative driver mutations affecting WNT (wingless-related integration site), JAK-STAT (Janus kinase/signal transducer and activator of transcription), or MAPK/PI3K (mitogen-activated kinase/phosphatidylinositol-3 kinase) pathways were found in all cases, aberrant activation of which converges on overexpression of MYC.

Extramedullary Tumor of Cerebral Falx: An Unusual Presentation of Acute Megakaryocytic Leukemia.

In childhood acute myelogenous leukemia, extramedullary tumor is an occasional clinical symptom. However, extramedullary acute megakaryocytic leukemia is extremely rare. Here, we report an extremely rare case of acute megakaryocytic leukemia in a patient who presented with extramedullary tumor of cerebral falx as a first manifestation before the diagnosis of systemic bone marrow leukemia.

Adult acute megakaryoblastic leukemia with persistent diarrhea and extreme thrombocytosis: A very unusual case.

ABSTRACT: Acute megakaryoblastic leukemia (AML-M7) is rarely seen in adult patients and patients usually present with cytopenias. Here we discuss diagnostic challenges and pathologic features in a patient with AML-M7 who presented with thrombocytosis and diarrhea. A 63-year-old male patient presented with persistent diarrhea lasting for 2 months, fatigue, and thrombocytosis. The diagnostic workup included a stool analysis, endoscopy colonoscopy, and imaging studies; however, these studies did not reveal any possible etiology. The hematologic evaluation included peripheral blood smear, bone marrow aspiration and biopsy, flow cytometry, and cytogenetic analysis. Eventually, according to pathologic and flow cytometric findings, a diagnosis of AML-M7 was made. Diagnosis of AML-M7 may be challenging, especially in adult patients with atypical presentation. Patients with megakaryoblastic leukemia respond poorly to standard induction regimens and they should be advised to participate in a clinical trial.

Skin Manifestations of Micafungin Breakthrough Disseminated Trichosporonosis in Acute Megakaryoblastic Leukemia.

Disseminated trichosporonosis is a rare fungal infection whose risk factors are hematological malignancies and neutropenia. Recently, breakthrough Trichosporon infections after administration of micafungin, the first-line systemic antifungal agent in compromised hosts, have been widely recognized. A man in his seventies about 1 month into chemotherapy for acute megakaryoblastic leukemia presented with a worsening fever and dyspnea. The patient was being administered with empirical micafungin therapy for suspected candidiasis. As the symptoms progressed, scattered erythema appeared on the trunk, some with a dark red vesicle at the center. Blood cultures identified Trichosporon asahii, as did the specimen of the skin biopsy. On the basis also of the presence of pneumonia on chest computed tomography, we confirmed the diagnosis of disseminated trichosporonosis and changed the antifungal agent from micafungin to voriconazole. Blood culture turned out to be negative 1 month after administrating voriconazole. However, the patient died of the leukemia. Our review of previous reports on cutaneous manifestations of disseminated trichosporonosis revealed that despite their morphological diversity, erythema with a red papule or vesicle at the center, implying necrosis, was also observed in previous cases. Our case report suggests that dermatologists should be aware of skin manifestations of disseminated trichosporonosis after micafungin administration, especially in cases of hematological malignancies.

Natural history of transient myeloproliferative disorder clinically diagnosed in Down syndrome neonates: a report from the Children's Oncology Group Study A2971.

Transient myeloproliferative disorder (TMD), restricted to newborns with trisomy 21, is a megakaryocytic leukemia that although lethal in some is distinguished by its spontaneous resolution. Later development of acute myeloid leukemia (AML) occurs in some. Prospective enrollment (n = 135) elucidated the natural history in Down syndrome (DS) patients diagnosed with TMD via the use of uniform monitoring and intervention guidelines. Prevalent at diagnosis were leukocytosis, peripheral blast exceeding marrow blast percentage, and hepatomegaly. Among those with life-threatening symptoms, most (n = 29/38; 76%) received intervention therapy until symptoms abated and then were monitored similarly. Organomegaly with cardiopulmonary compromise most frequently led to intervention (43%). Death occurred in 21% but only 10% were attributable to TMD (intervention vs observation patients: 13/14 vs 1/15 because of TMD). Among those solely observed, peripheral blasts and all other TMD symptoms cleared at a median of 36 and 49 days from diagnosis, respectively. On the basis of the diagnostic clinical findings of hepatomegaly with or without life-threatening symptoms, 3 groups were identified with differing survival: low risk with neither finding (38%), intermediate risk with hepatomegaly alone (40%), and high risk with both (21%; overall survival: 92% ± 8%, 77% ± 12%, and 51% ± 19%, respectively; P ≤ .001). Among all, AML subsequently occurred in 16% at a median of 441 days (range, 118-1085 days). The trial is registered at http://www.clinicaltrials.gov as NCT00003593.

Synergistic roles of DYRK1A and GATA1 in trisomy 21 megakaryopoiesis.

Patients with Down syndrome (DS), or trisomy 21 (T21), are at increased risk of transient abnormal myelopoiesis (TAM) and acute megakaryoblastic leukemia (ML-DS). Both TAM and ML-DS require prenatal somatic mutations in GATA1, resulting in the truncated isoform GATA1s. The mechanism by which individual chromosome 21 (HSA21) genes synergize with GATA1s for leukemic transformation is challenging to study, in part due to limited human cell models with wild-type GATA1 (wtGATA1) or GATA1s. HSA21-encoded DYRK1A is overexpressed in ML-DS and may be a therapeutic target. To determine how DYRK1A influences hematopoiesis in concert with GATA1s, we used gene editing to disrupt all 3 alleles of DYRK1A in isogenic T21 induced pluripotent stem cells (iPSCs) with and without the GATA1s mutation. Unexpectedly, hematopoietic differentiation revealed that DYRK1A loss combined with GATA1s leads to increased megakaryocyte proliferation and decreased maturation. This proliferative phenotype was associated with upregulation of D-type cyclins and hyperphosphorylation of Rb to allow E2F release and derepression of its downstream targets. Notably, DYRK1A loss had no effect in T21 iPSCs or megakaryocytes with wtGATA1. These surprising results suggest that DYRK1A and GATA1 may synergistically restrain megakaryocyte proliferation in T21 and that DYRK1A inhibition may not be a therapeutic option for GATA1s-associated leukemias.

Molecular lesions in childhood and adult acute megakaryoblastic leukaemia.

While acute megakaryoblastic leukaemia (AMKL) occurs in children with (DS-AMKL) and without (paediatric non-DS-AMKL) Down syndrome, it can also affect adults without DS (adult non-DS-AMKL). We have analysed these subgroups of patients (11 children with DS-AMKL, 12 children and four adults with non-DS-AMKL) for the presence of molecular lesions, including mutations and chromosomal abnormalities studied by sequencing and single nucleotide polymorphism array-based karyotyping, respectively. In children, AMKL was associated with trisomy 21 (somatic in non-DS-AMKL), while numerical aberrations of chromosome 21 were only rarely associated with adult AMKL. DS-AMKL was also associated with recurrent somatic gains of 1q (4/11 DS-AMKL patients). In contrast to trisomy 21 and gains of 1q, other additional chromosomal lesions were evenly distributed between children and adults with AMKL. A mutational screen found GATA1 mutations in 11/12 DS-AMKL, but mutations were rare in paediatric non-DS-AMKL (1/12) and adult AMKL (0/4). JAK3 (1/11), JAK2 (1/11), and TP53 mutations (1/11) were found only in patients with DS-AMKL. ASXL1, IDH1/2, DNMT3A, RUNX1 and CBL mutations were not found in any of the patient group studied, while NRAS mutation was identified in two patients with paediatric non-DS-AMKL.

Acute leukemias in children with Down syndrome.

Children with Down syndrome (DS) often present with hematopoietic abnormalities, and are at increased risk of developing leukemia. Specifically, 3-10% of newborns with DS are diagnosed with transient myeloproliferative disease, and children with DS are 500 times more likely to develop acute megakaryoblastic leukemia (AMKL) and 20 times more likely to develop acute lymphoblastic leukemia (ALL) than typical children. This review examines the characteristics of these leukemias and their development in the unique genetic background of trisomy 21. A discussion is also provided for areas of future research and potential therapeutic development.