ABSTRACT
Objective:To investigate the clinical features of acute megakaryocytic leukemia (AMKL) in children.Methods:The clinical data of 14 children with AMKL in Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology from January 2012 to July 2021 were retrospectively analyzed, and the related literature was reviewed.Results:Among 14 children with AMKL, there were 5 males and 9 females, and the median age of onset was 19 months (0.1-109 months); 1 case was Down syndrome-related AMKL, and 13 cases were non-Down syndrome-related AMKL. Most of the children presented with fever, anemia or bleeding symptoms, and a few patients presented with joint pain as the primary symptom. Some children were accompanied by extramedullary infiltration such as hepatomegaly, splenomegaly or lymphadenovarix. Initial investigations of 14 children showed that the median white blood count, hemoglobin concentration and platelet count were 10.67×10 9/L [(6.56-83.62)×10 9/L], 84 g/L (55-121 g/L), 37×10 9/L [(8-1443) ×10 9/L], respectively, and the median proportion of naive cells in peripheral blood was 0.09 (0.00-0.79). Bone marrow smear showed that the primitive megakaryocytes were characterized by various size and irregular form, a few of which had cytoplasmic vacuoles, and the median proportion of bone marrow primitive megakaryocytes was 0.636 (0.332-0.976); the nuclei were round or irregular, with multiple nucleoli or hidden nucleoli. RAS staining was partially positive, and immunohistochemical assay showed that POX, AS-DNCE and α-NBE were negative. Detection of megakaryocyte-associated antigens by flow cytometry showed 12 children expressed CD41a or CD61, and 10 children expressed CD42b. Among 3 children who completed chemotherapy, 1 case of Down syndrome-related AMKL and 1 case of non-Down syndrome-related AMKL were event-free survival, and 1 case of non-Down syndrome-related AMKL died after bone marrow relapse. Conclusions:The clinical manifestations and biological characteristics of children with AMKL are complicated and the prognosis is poor. Some children can achieve disease-free survival through chemotherapy alone.
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Objective To study the effect of metformin on the growth of megakaryocytic leukemia cell line Dami and to explore the molecular mechanisms of the inhibitory effect of metformin on the proliferation of Dami. Methods The Dami cells were cultured and divided into control and 1,2,4,8,16 and 32 mmol·L-1 metformin groups.Then MTT test was performed to detect the inhitory rate of proliferation of Dami cells after treated with different concentrations of metformin. Flow cytometry was used to examine the distribution of cell cycle, and Western blotting was carried out to analyze the expressions of Cdc2 and CylinB1 and the phosphorylation of Cdc2. Results The MTT results showed that compared with control group,the inhibitory rates of proliferation of the Dami cells in 32 mmol·L-1 metformin groups at 0,24,48,72 and 96 h (35.1%±2.3%,49.7%±5.1%, 78.85±0.9%,79.1%± 3.0%%,and 85.2%± 3.2%)were significantly increased(P<0.01),Furthermore, after metformin treatment for 72 h,the inhibitory rates of proliferation of the Dami cells in 1,2,4,8,16 and 32 mmol·L-1 metformin groups were (33.8 ± 0.3)%,(51.9 ± 0.2)%,(59.4 ± 1.6)%,(65.5 ± 2.0)%, (75.5±0.9)%,and (79.1±3.0)%,respectively. Metformin inhibited the growth of Dami cells in a time-and dose-dependent manner. The flow cytometry results results revealed that compared with control group, the percentages of Dami cells in G2/M phase in 1,2 and 4 mmol·L-1 metformin groups were increased from (26.0± 0.5)% to (38.5 ± 1.5 )%, (48.4 ± 1.1 )%, and (58.2 ± 2.7 )%;there was significant difference in the percentages of Dami cells in G2/M phase between control group and 4 mmol·L-1 metformin group (P<0.01). Western blotting analysis showed that compared with control group, the expressions of Cdc2 and CyclinB were evidently reduced, the phosophorylation of Cdc2 at Tyr1 5 was up-regulated, and the phosphorylation at Thr1 6 1 was down-regulated.Conclusion Metformin can inhibit the growth of Dami cells and induce G2/M arrest,and its mechanism may be related to inhibiting the activation of Cdc2/CyclinB1 complex.
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Objective To investigate the clinical data and laboratory features of acute megakaryocytic leukemia transformed from idiopathic myelofibrosis after 26 years in one case and the prognostic factors of myelofibrosis.Methods A case of acute megakaryocytic leukemia (M7) transformed from idiopathic myelofibrosis after 26 years was reported,and the clinical data was analyzed.Bone marrow cytology,cytogenetic and mutation detection in JAK2V617F were detected before and after transformation.Standard chemotherapeutic protocols including idarubicin plus cytarabine (IDA),homoharringtonine and cytarabine (HA),mitoxantrone and cytarabine (MA),pirarubicin plus cytarabine (TA) sequential therapies were performed.Results JAK2V617F mutation and normal karyotype were found before and after the transformation.This patient was treated with standard chemotherapeutic protocols of IDA,HA,MA and TA sequential therapies until getting complete remission,and he lived well till now.Conclusions Chromosome karyotype is related to the prognosis of IMF.Acute megakaryocytic leukemia (M7) with the normal karyotype transformed from the IMF can achieve complete remission by rational consecutive chemotherapy.
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Although acquired mutations in the GATA1 gene have been reported for Down syndrome-related acute megakaryoblastic leukemia (DS-AMKL) in Caucasians, this is the first report of a Korean Down syndrome patient with AMKL carrying a novel mutation of the GATA1 gene. A 3-yr-old Korean girl with Down syndrome was admitted to our hospital complaining of pallor and fever. The findings of a peripheral blood smear and bone marrow study were compatible with the presence of AMKL. A chromosome study showed 48,XX,-7,+21c,+21,+r[3]/47,XX,+21c[17]. Following GATA1 gene mutation analysis, a novel mutation, c.145dupG (p.Ala49GlyfsX18), was identified in the N-terminal activation domain of the GATA1 gene. This mutation caused a premature termination at codon 67 and expression of an abnormal GATA-1 protein with a defective N-terminal activation domain, and the absence of full-length GATA-1 protein. This case demonstrates that a leukemogenic mechanism for DS-AMKL is contributed by a unique collaboration between overexpressed genes from trisomy 21 and an acquired GATA1 mutation previously seen in Caucasians and now in a Korean patient.