Clinical Analysis of Pediatric Acute Megakaryocytic Leukemia With CBFA2T3-GLIS2 Fusion Gene.

CBFA2T3-GLIS2 is the most frequent chimeric oncogene identified to date in non-Down syndrome acute megakaryocytic leukemia (AMKL), which is associated with extremely poor clinical outcome. The presence of this fusion gene is associated with resistance to high-intensity chemotherapy, including hematopoietic stem cell transplantation (HSCT), and a high cumulative incidence of relapse frequency. The clinical features and clinical effects of China Children's Leukemia Group-acute myeloid leukemia (AML) 2015/2019 regimens and haploidentical HSCT (haplo-HSCT) for treatment of 6 children harboring the CBFA2T3-GLIS2 fusion gene between January 2019 and December 2021 were retrospectively analyzed. The 6 patients included 4 boys and 2 girls with a median disease-onset age of 19.5 months (range: 6-67 mo) who were diagnosed with AMKL. Flow cytometry demonstrated CD41a, CD42b, and CD56 expression and lack of HLA-DR expression in all 6 patients. All the children were negative for common leukemia fusion genes by reverse transcription polymerase chain reaction, but positive for the CBFA2T3-GLIS2 fusion gene by next-generation sequencing and RNA sequencing. All patients received chemotherapy according to China Children's Leukemia Group-AML 2015/2019 regimens, and 4 achieved complete remission. Four children underwent haplo-HSCT with posttransplant cyclophosphamide-based conditioning; 3 had minimal residual disease negative (minimal residual disease <0.1%) confirmed by flow cytometry at the end of the follow-up, with the remaining patient experiencing relapse at 12 months after transplantation. Transcriptome RNA sequencing is required for the detection of the CBFA2T3-GLIS2 fusion gene and for proper risk-based allocation of pediatric patients with AML in future clinical strategies. Haplo-HSCT with posttransplant cyclophosphamide-based conditioning may improve survival in children with AMKL harboring the fusion gene.

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.

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.

Acute monocytic leukemia with KMT2A::LASP1 developed 9 months after diagnosis of acute megakaryoblastic leukemia in a 2-year-old boy.

Acute myeloid leukemia (AML) is known as one of the subsequent malignant neoplasms that can develop after cancer treatment, but it is difficult to distinguish from relapse when the preceding cancer is leukemia. We report a 2-year-old boy who developed acute megakaryoblastic leukemia (AMKL, French-American-British classification [FAB]: M7) at 18 months of age and achieved complete remission with multi-agent chemotherapy without hematopoietic stem cell transplantation. Nine months after diagnosis and 4 months after completing treatment for AMKL, he developed acute monocytic leukemia (AMoL) with the KMT2A::LASP1 chimeric gene (FAB: M5b). The second complete remission was achieved using multi-agent chemotherapy and he underwent cord blood transplantation 4 months after AMoL was diagnosed. He is currently alive and disease free at 39 and 48 months since his AMoL and AMKL diagnoses, respectively. Retrospective analysis revealed that the KMT2A::LASP1 chimeric gene was detected 4 months after diagnosis of AMKL. Common somatic mutations were not detected in AMKL or AMoL and no germline pathogenic variants were detected. Since the patient's AMoL was different from his primary leukemia of AMKL in terms of morphological, genomic, and molecular analysis, we concluded that he developed a subsequent leukemia rather than a relapse of his primary leukemia.

Mixed-phenotype acute leukemia, T/megakaryoblastic: does it really exist?

Mixed-phenotype acute leukemias (MPAL) account for < 4% of all cases of acute leukemias. These are a heterogeneous group of leukemias grouped together by the WHO classification as "rare subtypes." The diagnosis and treatment of MPAL is extremely challenging particularly for low middle income countries. Of these, B/myeloid and T/myeloid combinations are relatively common subtypes. However, megakaryoblastic and erythroid lineages in combination with other lineages are still rare enough to not even be addressed in the WHO classification. To date, there have been only a few reports of mixed B or T cell and megakaryocytic or mixed B or T cell and erythroid leukemias. We report the clinical presentation, diagnostic profile, and disease course of MPAL cases with a biphenotypic pattern consistent with T/megakaryoblastic lineage which is not yet defined in WHO classification. These cases were phenotyped using 8-color flow cytometry (BD FACS CANTO-II) using an extensive panel of markers. Interphase fluorescence in situ hybridization (FISH) was done using dual color dual fusion probes for BCR::ABL1, RUNX1::RUNX1T1, and ETV6::RUNX1, while MLL and CBFB gene rearrangement was tested by break-apart probes. Karyotyping was performed using the conventional GTG-banding technique. Both FISH and karyotyping were analyzed by the automated cell imaging system Leica Biosystems, using Cytovision MB8. The cases presented here satisfy the criteria for both T-lineage assignment (cyCD3 intensity reaches that of normal T-lymphocytes) and acute megakaryoblastic leukemia (≥ 1 megakaryocytic marker in > 50% blasts) and thus represent the first documented examples of this unusual entity from Pakistan. It is crucial to report these cases to gather more data about clinical presentation, diagnostic profile, and disease course. Additionally, the reported cases highlight the limitations of existing classifications which do not address rare subtypes. More importantly, T/megakaryoblastic MPAL needs to be included in the WHO classification as a separate entity.

Acute megakaryoblastic leukemia with trisomy 3 and CBFA2T3::GLIS2: A case report.

Non-Down-syndrome-related acute megakaryoblastic leukemia (non-DS-AMKL) is a rare form of leukemia that can present with a variety of initial symptoms, including fever, rash, bruising, bleeding, or other more clinically challenging symptoms. Herein, we describe a 19-month-old female patient who presented with left lower extremity pain and language regression who was diagnosed with AMKL, not otherwise specified (NOS), on the basis of peripheral blood and bone marrow analysis, as well as cytogenetic and molecular diagnostic phenotyping. Of note, in addition to this patient's karyotype showing trisomy 3, a fusion between CBFA2T3 (core-binding factor, alpha subunit 2, translocated to, 3) on chromosome 16 and GLIS2 (GLIS family zinc finger protein 2), also on chromosome 16, was observed. Patients with AMKL who have trisomy 3 with CBFA2T3::GLIS2 fusions are rare, and it is not known if the co-occurrence of these abnormalities is coincidental or biologically related. This highlights the continued need for further expansion of genetic testing in individuals with rare disease to establish the groundwork for identifying additional commonalities that could potentially be used to identify therapeutic targets or improve prognostication.

Sensitive detection of GATA1 mutations using complementary DNA-based analysis for transient abnormal myelopoiesis associated with the Down syndrome.

INTRODUCTION: GATA1 mutation plays an important role in initiating transient abnormal myelopoiesis (TAM) and in the clonal evolution towards acute megakaryoblastic leukaemia (AMKL) associated with Down syndrome (DS). This study aimed to develop and validate the clinical utility of a complementary DNA (cDNA) analysis in parallel with the conventional genomic DNA (gDNA) Sanger sequencing (Ss), as an initial screening test for GATA1 mutations. METHODS: GATA1 mutations were evaluated using both gDNA and cDNA in 14 DS patients using Ss and fragment analysis (FA), respectively. RESULTS: The detection sensitivity of conventional gDNA sequencing was limited in low blast percentage TAM (LBP-TAM); however, cDNA-based Ss readily detected all the pathognomonic GATA1 mutations. The cDNA-based FA readily detected GATA1 frameshift mutation with a reliable sensitivity ranging from 0.005% to 0.01% of clonal cells. CONCLUSIONS: GATA1 mutations are heterogeneous; therefore, we would like to propose a dual cDNA and gDNA analysis as a standard diagnostic approach, especially for LBP-TAM. cDNA-based FA promises an excellent sensitivity for detecting frameshift GATA1 mutations in the longitudinal clonal evolution towards AMKL without using a patient specific primer.

Pathological and immunohistochemical aspects of acute megakaryoblastic leukaemia in a cat - Short communication.

An adult, mixed-breed, feline leukaemia virus (FeLV-) positive female cat was presented with mucosal jaundice and a history of anorexia and constipation for three days. Physical examination revealed splenomegaly, cachexia, and dehydration. Humane euthanasia was conducted, followed by postmortem examination. Grossly, the cat was icteric, and presented hepatomegaly with multifocal white spots and splenomegaly. Histologically, the bone marrow was nearly completely replaced by a proliferation of megakaryocytes and megakaryoblasts, and there was a proliferation of fibrous connective tissue. Similar neoplastic proliferation was observed infiltrating the liver, lymph nodes, spleen, kidney, skeletal muscle, and lungs. Immunohistochemistry was performed for von Willebrand Factor (VWF), CD79α, CD3, feline immunodeficiency virus, FeLV, and CD61. Marked cytoplasmic labelling was observed in the neoplastic cells for FeLV, VWF and CD61, corroborating the diagnosis of acute megakaryoblastic leukaemia.

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.

TP53 and PTEN mutations were shared in concurrent germ cell tumor and acute megakaryoblastic leukemia.

BACKGROUND: The occurrence of a mediastinal germ cell tumor (GCT) and hematological malignancy in the same patient is very rare. Due to its rarity, there have been only two reports of the concurrent cases undergoing detailed genetic analysis with whole-exome sequencing (WES), and the possible clonal relationship between the both tumors remained not fully elucidated. METHODS: We performed whole-exome sequencing analysis of mediastinal GCT and acute myeloid leukemia (AML) samples obtained from one young Japanese male adult patient with concurrent both tumors, and investigated the possible clonal relationship between them. RESULTS: Sixteen somatic mutations were detected in the mediastinal GCT sample and 18 somatic mutations in the AML sample. Mutations in nine genes, including TP53 and PTEN both known as tumor suppressor genes, were shared in both tumors. CONCLUSIONS: All in our case and in the previous two cases with concurrent mediastinal GCT and AML undergoing with whole-exome sequencing analysis, TP53 and PTEN mutations were commonly shared in both tumors. These data not only suggest that these tumors share a common founding clone, but also indicate that associated mediastinal GCT and AML harboring TP53 and PTEN mutations represent a unique biological entity.

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.