Publications by authors named "Myoung-Ja Park"

36 Publications

Clinical features of 35 Down syndrome patients with transient abnormal myelopoiesis at a single institution.

Int J Hematol 2021 May 4;113(5):662-667. Epub 2021 Jan 4.

Department of Hematology/Oncology, Gunma Children's Medical Center, Shibukawa, Gunma, Japan.

Transient abnormal myelopoiesis (TAM) is a unique clonal myeloproliferation characterized by immature megakaryoblasts that occurs in 5-10% of neonates with Down syndrome (DS). Although TAM regresses spontaneously in most patients, approximately 20% of TAM cases result in early death, and approximately 20% of survivors develop acute megakaryoblastic leukemia (AMKL). We retrospectively reviewed records of 35 DS patients with TAM to determine the correlation between clinical characteristics and blast percentage. Thirteen of the 35 patients were classified as low blast percentage TAM (LBP-TAM), defined as TAM with a peak peripheral blast percentage ≤ 10%. Although no patient with LBP-TAM experienced systemic edema, disseminated intravascular coagulation, or early death, eight patients had elevated direct bilirubin levels (> 2 mg/dl) and one developed AMKL. All patients with LBP-TAM had serum markers of liver fibrosis that exceeded the normal limits, and two patients underwent liver biopsy to clarify the etiology of pathological jaundice. Taken together, our results suggest that patients with LBP-TAM may be at risk of liver fibrosis and liver failure, similarly to patients with classical TAM. Although these patients generally have a good prognosis, they should be carefully monitored for potential development of liver disease and leukemia.
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http://dx.doi.org/10.1007/s12185-020-03066-7DOI Listing
May 2021

Inherited chromosomally integrated human herpesvirus-6 in a patient with XIAP deficiency.

Transpl Infect Dis 2020 Oct 8;22(5):e13331. Epub 2020 Jun 8.

Deprtment of Child Health and Development, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.

Human herpesvirus-6 (HHV-6) is a common pathogen affecting the human population. Primary HHV-6 infection generally occurs during infancy and causes exanthema subitum. Moreover, HHV-6 may exhibit inherited chromosomally integrated HHV-6 (iciHHV-6) in certain individuals. Although iciHHV-6 is generally known to be nonpathogenic, it may cause reactivation in patients with primary immunodeficiency disease (PID). XIAP deficiency is a rare PID characterized by recurrent hemophagocytic lymphohistiocytosis (HLH). It has been reported that the Epstein-Barr virus primarily causes HLH; however, the other pathogens, including HHV-6, can also cause this complication. We encountered a case of XIAP deficiency accompanied by iciHHV-6. He suffered from recurrent HLH, for which allogeneic bone marrow transplantation (BMT) was performed as a curative therapy. During the course of BMT, the patient experienced HLH three times, but there was no reactivation of endogenous HHV-6 from iciHHV-6. Finally, the patient achieved complete donor chimerism and a decline in HHV-6 DNA copy number in whole blood. This case report demonstrates no evidence of reactivation of iciHHV-6 during BMT in a patient with XIAP deficiency.
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http://dx.doi.org/10.1111/tid.13331DOI Listing
October 2020

Clinical and molecular characteristics of fusion-positive B-cell precursor acute lymphoblastic leukemia in childhood, including a novel translocation resulting in gene fusion.

Haematologica 2019 01 31;104(1):128-137. Epub 2018 Aug 31.

Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo.

Fusion genes involving have recently been identified in precursor B-cell acute lymphoblastic leukemia, mutually exclusive of the common risk stratifying genetic abnormalities, although their true incidence and associated clinical characteristics remain unknown. We identified 16 cases of acute lymphoblastic leukemia and 1 of lymphoma harboring fusions, including (n=10), (n=6), and one novel fusion. The incidence of fusions overall was 2.4% among consecutive precursor B-cell acute lymphoblastic leukemia patients enrolled onto a single clinical trial. They frequently showed a cytoplasmic μ chain-positive pre-B immunophenotype, and often expressed an aberrant CD5 antigen. Besides up- and down-regulation of and , elevated expression was also a characteristic feature of fusion-positive patients. Mutations of , recurrent in T-cell acute lymphoblastic leukemia, also showed an unexpectedly high frequency (50%) in these patients. fusion-positive patients were older (median age 9 years) with elevated WBC counts (median: 27,300/ml) at presentation and, as a result, were mostly classified as NCI high risk. Although they responded well to steroid treatment, fusion-positive patients showed a significantly worse outcome, with 53.3% relapse and subsequent death. Stem cell transplantation was ineffective as salvage therapy. Interestingly, relapse was frequently associated with the presence of gene deletions. Our observations indicate that fusions comprise a distinct subgroup of precursor B-cell acute lymphoblastic leukemia with a characteristic immunophenotype and gene expression signature, associated with distinct clinical features.
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http://dx.doi.org/10.3324/haematol.2017.186320DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6312004PMC
January 2019

Clinical features and prognostic impact of PRDM16 expression in adult acute myeloid leukemia.

Genes Chromosomes Cancer 2017 11 11;56(11):800-809. Epub 2017 Aug 11.

Department of Hematology/Oncology, Gunma Children's Medical Center, Gunma, Japan.

High PRDM16 (also known as MEL1) expression is a representative marker of acute myeloid leukemia (AML) with NUP98-NSD1 and is a significant predictive marker for poor prognosis in pediatric AML. However, the clinical features of adult AML with PRDM16 expression remain unclear. PRDM16 is highly homologous to MDS1/EVI1, which is an alternatively spliced transcript of MECOM (also known as EVI1). We investigated PRDM16 expression in 151 AML patients, with 47 (31%) exhibiting high PRDM16 expression (PRDM16/ABL1 ratio ≥ 0.010). High PRDM16 expression significantly correlated with DNMT3A (43% vs. 15%, P < 0.001) and NPM1 (43% vs. 21%, P = 0.010) mutations and partial tandem duplication of KMT2A (22% vs. 1%, P < 0.001). Remarkably, high-PRDM16-expression patients were frequent in the noncomplete remission group (48% vs. 21%, P = 0.002). Overall survival (OS) was significantly worse in high-PRDM16-expression patients than in low-PRDM16-expression patients (5-year OS, 18% vs. 34%; P = 0.002). This trend was observed more clearly among patients aged <65 years (5-year OS, 21% vs. 50%; P = 0.001), particularly in FLT3-ITD-negative patients in the intermediate cytogenetic risk group (5-year OS, 25% vs. 59%; P = 0.009). These results suggest that high PRDM16 expression is a significant predictive marker for poor prognosis in adult AML patients, similar to pediatric AML patients.
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http://dx.doi.org/10.1002/gcc.22483DOI Listing
November 2017

ASXL2 mutations are frequently found in pediatric AML patients with t(8;21)/ RUNX1-RUNX1T1 and associated with a better prognosis.

Genes Chromosomes Cancer 2017 05 14;56(5):382-393. Epub 2017 Feb 14.

Department of Hematology/Oncology, Gunma Children's Medical Center, Gunma, Japan.

ASXL2 is an epigenetic regulator involved in polycomb repressive complex regulation or recruitment. Clinical features of pediatric acute myeloid leukemia (AML) patients with ASXL2 mutations remain unclear. Thus, we investigated frequencies of ASXL1 and ASXL2 mutations, clinical features of patients with these mutations, correlations of these mutations with other genetic alterations including BCOR/BCORL1 and cohesin complex component genes, and prognostic impact of these mutations in 369 pediatric patients with de novo AML (0-17 years). We identified 9 (2.4%) ASXL1 and 17 (4.6%) ASXL2 mutations in 25 patients. These mutations were more common in patients with t(8;21)(q22;q22)/RUNX1-RUNX1T1 (ASXL1, 6/9, 67%, P = 0.02; ASXL2, 10/17, 59%, P = 0.01). Among these 25 patients, 4 (27%) of 15 patients with t(8;21) and 6 (60%) of 10 patients without t(8;21) relapsed. However, most patients with relapse were rescued using stem cell transplantation irrespective of t(8;21). The overall survival (OS) and event-free survival (EFS) rates showed no differences among pediatric AML patients with t(8;21) and ASXL1 or ASXL2 mutations and ASXL wild-type (5-year OS, 75% vs. 100% vs. 91% and 5-year EFS, 67% vs. 80% vs. 67%). In 106 patients with t(8;21) AML, the coexistence of mutations in tyrosine kinase pathways and chromatin modifiers and/or cohesin complex component genes had no effect on prognosis. These results suggest that ASXL1 and ASXL2 mutations play key roles as cooperating mutations that induce leukemogenesis, particularly in pediatric AML patients with t(8;21), and these mutations might be associated with a better prognosis than that reported previously.
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http://dx.doi.org/10.1002/gcc.22443DOI Listing
May 2017

Prognostic impact of specific molecular profiles in pediatric acute megakaryoblastic leukemia in non-Down syndrome.

Genes Chromosomes Cancer 2017 05 14;56(5):394-404. Epub 2017 Feb 14.

Department of Hematology and Oncology, Gunma Children's Medical Center, Shibukawa, Japan.

Pediatric acute megakaryoblastic leukemia in non-Down syndrome (AMKL) is a unique subtype of acute myeloid leukemia (AML). Novel CBFA2T3-GLIS2 and NUP98-KDM5A fusions recurrently found in AMKL were recently reported as poor prognostic factors. However, their detailed clinical and molecular characteristics in patients treated with recent improved therapies remain uncertain. We analyzed molecular features of 44 AMKL patients treated on two recent Japanese AML protocols, the AML99 and AML-05 trials. We identified CBFA2T3-GLIS2, NUP98-KDM5A, RBM15-MKL1, and KMT2A rearrangements in 12 (27%), 4 (9%), 2 (5%), and 3 (7%) patients, respectively. Among 459 other AML patients, NUP98-KDM5A was identified in 3 patients, whereas CBFA2T3-GLIS2 and RBM15-MKL1 were only present in AMKL. GATA1 mutations were found in 5 patients (11%). Four-year overall survival (OS) and event-free survival (EFS) rates of CBFA2T3-GLIS2-positive patients in AMKL were 41.7% and 16.7%, respectively. Three-year cumulative incidence of relapse in CBFA2T3-GLIS2-positive patients was significantly higher than that of CBFA2T3-GLIS2-negative patients (75.0% vs. 35.7%, P = 0.024). In multivariate analyses, CBFA2T3-GLIS2 was an independent poor prognostic factor for OS (HR, 4.34; 95% CI, 1.31-14.38) and EFS (HR, 2.95; 95% CI, 1.20-7.23). Furthermore, seven (54%) of 13 infant AMKL patients were CBFA2T3-GLIS2-positive. Notably, out of 7 CBFA2T3-GLIS2-positive infants, six (86%) relapsed and five (71%) died. Moreover, all of CBFA2T3-GLIS2-positive patients who experienced induction failure (n = 3) were infants, indicating worse prognosis of CBFA2T3-GLIS2-positive infants. These findings indicated the significance of CBFA2T3-GLIS2 as a poor prognostic factor in AMKL patients, particularly in infants.
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http://dx.doi.org/10.1002/gcc.22444DOI Listing
May 2017

Whole-exome sequencing reveals the spectrum of gene mutations and the clonal evolution patterns in paediatric acute myeloid leukaemia.

Br J Haematol 2016 Nov 29;175(3):476-489. Epub 2016 Jul 29.

Department of Haematology/Oncology, Gunma Children's Medical Centre, Shibukawa, Japan.

Acute myeloid leukaemia (AML) is a molecularly and clinically heterogeneous disease. Targeted sequencing efforts have identified several mutations with diagnostic and prognostic values in KIT, NPM1, CEBPA and FLT3 in both adult and paediatric AML. In addition, massively parallel sequencing enabled the discovery of recurrent mutations (i.e. IDH1/2 and DNMT3A) in adult AML. In this study, whole-exome sequencing (WES) of 22 paediatric AML patients revealed mutations in components of the cohesin complex (RAD21 and SMC3), BCORL1 and ASXL2 in addition to previously known gene mutations. We also revealed intratumoural heterogeneities in many patients, implicating multiple clonal evolution events in the development of AML. Furthermore, targeted deep sequencing in 182 paediatric AML patients identified three major categories of recurrently mutated genes: cohesion complex genes [STAG2, RAD21 and SMC3 in 17 patients (8·3%)], epigenetic regulators [ASXL1/ASXL2 in 17 patients (8·3%), BCOR/BCORL1 in 7 patients (3·4%)] and signalling molecules. We also performed WES in four patients with relapsed AML. Relapsed AML evolved from one of the subclones at the initial phase and was accompanied by many additional mutations, including common driver mutations that were absent or existed only with lower allele frequency in the diagnostic samples, indicating a multistep process causing leukaemia recurrence.
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http://dx.doi.org/10.1111/bjh.14247DOI Listing
November 2016

High PRDM16 expression identifies a prognostic subgroup of pediatric acute myeloid leukaemia correlated to FLT3-ITD, KMT2A-PTD, and NUP98-NSD1: the results of the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 trial.

Br J Haematol 2016 Feb 18;172(4):581-91. Epub 2015 Dec 18.

Department of Haematology/Oncology, Gunma Children's Medical Centre, Shibukawa, Japan.

Recent reports described the NUP98-NSD1 fusion as an adverse prognostic marker for acute myeloid leukaemia (AML) and PRDM16 (also known as MEL1) as the representative overexpressed gene in patients harbouring NUP98-NSD1 fusion. PRDM16 gene expression levels were measured via real-time polymerase chain reaction in 369 paediatric patients with de novo AML, of whom 84 (23%) exhibited PRDM16 overexpression (PRDM16/ABL1 ratio ≥0·010). The frequencies of patients with high or low PRDM16 expression differed widely with respect to each genetic alteration, as follows: t(8;21), 4% vs. 96%, P < 0·001; inv(16), 0% vs. 100%, P < 0·001; KMT2A (also termed MLL)- partial tandem duplication, 100% vs. 0%, P < 0·001; NUP98-NSD1, 100% vs. 0%, P < 0·001. The overall survival (OS) and event-free survival (EFS) among PRDM16-overexpressing patients were significantly worse than in patients with low PRDM16 expression (3-year OS: 51% vs. 81%, P < 0·001, 3-year EFS: 32% vs. 64%, P < 0·001) irrespective of other cytogenetic alterations except for NPM1. PRDM16 gene expression was particularly useful for stratifying FLT3-internal tandem duplication-positive AML patients (3-year OS: high = 30% vs. low = 70%, P < 0·001). PRDM16 overexpression was highly recurrent in de novo paediatric AML patients with high/intermediate-risk cytogenetic profiles and was independently associated with an adverse outcome.
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http://dx.doi.org/10.1111/bjh.13869DOI Listing
February 2016

CSF3R and CALR mutations in paediatric myeloid disorders and the association of CSF3R mutations with translocations, including t(8; 21).

Br J Haematol 2015 Aug 9;170(3):391-7. Epub 2015 Apr 9.

Department of Haematology/Oncology, Gunma Children's Medical Centre, Shibukawa, Japan.

Mutations in the colony-stimulating factor 3 receptor (CSF3R) and calreticulin (CALR) genes have been reported in a proportion of adults with myeloproliferative disease. However, little is known about CSF3R or CALR mutations in paediatric myeloid disorders. We analysed CSF3R exons 14 and 17, and CALR exon 9, using direct sequencing in samples of paediatric acute myeloid leukaemia (AML; n = 521), juvenile myelomonocytic leukaemia (JMML; n = 40), myelodysplastic syndrome (MDS; n = 20) and essential thrombocythaemia (ET; n = 21). CSF3R mutations were found in 10 (1.2%) of 521 patients with AML; two in exon 14 (both missense mutations resulting in p.T618I) and eight in exon 17 (three frameshift mutations: p.S715X, p.Q774R, and p.S783Q; and five novel missense mutations: p.Q754K, p.R769H, p.L777F, p.T781I, and S795R). All of the patients with mutations in CSF3R exon 17 had chromosomal translocations, including four with t(8;21). At the time of reporting, seven of these ten patients are alive; three have died, due to side effects of chemotherapy. No CSF3R mutations were found in cases of MDS, JMML or ET. The only mutation found in the CALR gene was a frameshift (p.L367 fs) in one ET patient. We discuss the potential impact of these findings for the leukaemogenesis and clinical features of paediatric myeloid disorders.
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http://dx.doi.org/10.1111/bjh.13439DOI Listing
August 2015

Biallelic DICER1 mutations in sporadic pleuropulmonary blastoma.

Cancer Res 2014 May 27;74(10):2742-9. Epub 2014 Mar 27.

Authors' Affiliations: Department of Pediatrics; Cancer Genomics Project, Graduate School of Medicine; Laboratory of DNA Information Analysis and Sequence Data Analysis, Human Genome Center, Institute of Medical Science; Department of Cell Therapy and Transplantation Medicine, The University of Tokyo, Tokyo; Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Kyoto; Division of Pediatric Hematology and Oncology, Ibaraki Children's Hospital, Mito, Ibaraki; Department of Hematology/Oncology, Saitama Children's Medical Center, Saitama, Saitama; Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka; Gunma Children's Medical Center, Shibukawa, Gunma; Department of Hematology and Oncology, Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo; and National Center for Child Health and Development, Tokyo, Japan

Pleuropulmonary blastoma (PPB) is a rare pediatric malignancy whose pathogens are poorly understood. Recent reports suggest that germline mutations in the microRNA-processing enzyme DICER1 may contribute to PPB development. To investigate the genetic basis of this cancer, we performed whole-exome sequencing or targeted deep sequencing of multiple cases of PPB. We found biallelic DICER1 mutations to be very common, more common than TP53 mutations also found in many tumors. Somatic ribonuclease III (RNase IIIb) domain mutations were identified in all evaluable cases, either in the presence or absence of nonsense/frameshift mutations. Most cases had mutated DICER1 alleles in the germline with or without an additional somatic mutation in the remaining allele, whereas other cases displayed somatic mutations exclusively where the RNase IIIb domain was invariably affected. Our results highlight the role of RNase IIIb domain mutations in DICER1 along with TP53 inactivation in PPB pathogenesis.
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http://dx.doi.org/10.1158/0008-5472.CAN-13-2470DOI Listing
May 2014

Liver disease is frequently observed in Down syndrome patients with transient abnormal myelopoiesis.

Int J Hematol 2014 Feb 14;99(2):154-61. Epub 2013 Dec 14.

Department of Hematology/Oncology, Gunma Children's Medical Center, 779 Shimohakoda, Hokkitsu, Shibukawa, Gunma, 377-8577, Japan,

Transient abnormal myelopoiesis (TAM) in neonates with Down syndrome (DS) is characterized by the transient appearance of blast cells, which resolves spontaneously. Approximately 20 % of patients with TAM die at an early age due to organ failure, including liver disease. We studied 25 DS-TAM patients retrospectively to clarify the correlation between clinical and laboratory characteristics and liver diseases. Early death (<6 months of age) occurred in four of the 25 patients (16.0 %), and two of those four patients died due to liver failure. Although physiologic jaundice improved gradually after a week, all DS patients had elevated D-Bil levels during the clinical course of TAM, except one who suffered early death. The median peak day of the WBC count, total bilirubin (T-Bil) and D-Bil levels was: day 1 (range day 0-57), day 8 (range day 1-55), and day 17 (range 1-53), respectively. Our results reveal that all patients with DS-TAM may develop liver disease irrespective of the absence or presence of symptoms and risk factors for early death. In patients of DS-TAM, careful observation of the level of D-Bil is needed by at least 1 month of age for the detection of liver disease risk.
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http://dx.doi.org/10.1007/s12185-013-1487-5DOI Listing
February 2014

SETBP1 mutations in juvenile myelomonocytic leukaemia and myelodysplastic syndrome but not in paediatric acute myeloid leukaemia.

Br J Haematol 2014 Jan 14;164(1):156-9. Epub 2013 Oct 14.

Department of Haematology/Oncology, Gunma Children's Medical Centre, Gunma, Japan; Department of Paediatrics, Gunma University Graduate School of Medicine, Gunma, Japan.

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http://dx.doi.org/10.1111/bjh.12595DOI Listing
January 2014

The landscape of somatic mutations in Down syndrome-related myeloid disorders.

Nat Genet 2013 Nov 22;45(11):1293-9. Epub 2013 Sep 22.

1] Cancer Genomics Project, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. [2] Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. [3].

Transient abnormal myelopoiesis (TAM) is a myeloid proliferation resembling acute megakaryoblastic leukemia (AMKL), mostly affecting perinatal infants with Down syndrome. Although self-limiting in a majority of cases, TAM may evolve as non-self-limiting AMKL after spontaneous remission (DS-AMKL). Pathogenesis of these Down syndrome-related myeloid disorders is poorly understood, except for GATA1 mutations found in most cases. Here we report genomic profiling of 41 TAM, 49 DS-AMKL and 19 non-DS-AMKL samples, including whole-genome and/or whole-exome sequencing of 15 TAM and 14 DS-AMKL samples. TAM appears to be caused by a single GATA1 mutation and constitutive trisomy 21. Subsequent AMKL evolves from a pre-existing TAM clone through the acquisition of additional mutations, with major mutational targets including multiple cohesin components (53%), CTCF (20%), and EZH2, KANSL1 and other epigenetic regulators (45%), as well as common signaling pathways, such as the JAK family kinases, MPL, SH2B3 (LNK) and multiple RAS pathway genes (47%).
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http://dx.doi.org/10.1038/ng.2759DOI Listing
November 2013

Mutations of the GATA2 and CEBPA genes in paediatric acute myeloid leukaemia.

Br J Haematol 2014 Jan 14;164(1):142-5. Epub 2013 Sep 14.

Department of Haematology/Oncology, Gunma Children's Medical Centre, Shibukawa, Japan; Department of Paediatrics, Gunma University Graduate School of Medicine, Maebashi, Japan.

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http://dx.doi.org/10.1111/bjh.12559DOI Listing
January 2014

WT1 mutation in pediatric patients with acute myeloid leukemia: a report from the Japanese Childhood AML Cooperative Study Group.

Int J Hematol 2013 Oct 27;98(4):437-45. Epub 2013 Aug 27.

Department of Hematology/Oncology, Gunma Children's Medical Center, 779 Shimohakoda, Hokkitsu, Shibukawa, Gunma, 377-8577, Japan.

Mutations in Wilms tumor 1 (WT1) have been reported in 10-22 % of patients with cytogenetically normal acute myeloid leukemia (CN-AML), but the prognostic implications of these abnormalities have not been clarified in either adults or children. One hundred and fifty-seven pediatric AML patients were analyzed for WT1 mutations around hotspots at exons 7 and 9; however, amplification of the WT1 gene by the reverse transcriptase-polymerase chain reaction was not completed in four cases (2.5 %). Of the 153 evaluable patients, 10 patients (6.5 %) had a mutation in WT1. The incidence of WT1 mutations was significantly higher in CN-AML than in others (15.2 vs. 4.5 %, respectively, P = 0.03). Of the 10 WT1-mutated cases, eight (80 %) had mutations in other genes, including FLT3-ITD in two cases, FLT3-D835 mutation in two, KIT mutation in three, MLL-PTD in three, NRAS mutation in one, and KRAS mutation in two (in some cases, more than one additional gene was mutated). The incidences of KIT and FLT3-D835 mutations were significantly higher in patients with than in those without WT1 mutation. No significant differences were observed in the 3-year overall survival and disease-free survival; however, the presence of WT1 mutation was related to a poor prognosis in patients with CN-AML, excluding those with FLT3-ITD and those younger than 3 years.
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http://dx.doi.org/10.1007/s12185-013-1409-6DOI Listing
October 2013

Mutational analyses of the ATP6V1B1 and ATP6V0A4 genes in patients with primary distal renal tubular acidosis.

Nephrol Dial Transplant 2013 Aug 31;28(8):2123-30. Epub 2013 May 31.

Department of Pediatrics, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.

Background: Mutations in the ATP6V1B1 and the ATP6V0A4 genes cause primary autosomal-recessive distal renal tubular acidosis (dRTA). Large deletions of either gene in patients with dRTA have not been described.

Methods: The ATP6V1B1 and ATP6V0A4 genes were directly sequenced in 11 Japanese patients with primary dRTA from nine unrelated kindreds. Large heterozygous deletions were analyzed by quantitative real-time polymerase chain reaction (PCR). The clinical features of the 11 patients were also investigated.

Results: Novel mutations in the ATP6V1B1 gene were identified in two kindreds, including frameshift, in-frame insertion and nonsense mutations. Large deletions in the ATP6V0A4 gene were identified in two kindreds. Exon 15 of ATP6V0A4 was not amplified in one patient, with a long PCR confirming compound heterozygous deletions of 3.7- and 6.9-kb nucleotides, including all of exon 15. Direct DNA sequencing revealed a heterozygous frameshift mutation in ATP6V0A4 in another patient, with quantitative real-time PCR indicating that all exons up to exon 8 were deleted in one allele. Clinical investigation showed that four of the six patients with available clinical data presented with hyperammonemia at onset.

Conclusions: To our knowledge, these dRTA patients are the first to show large deletions involving one or more entire exons of the ATP6V0A4 gene. Quantitative PCR amplification may be useful in detecting heterozygous large deletions. These results expand the spectrum of mutations in the ATP6V0A4 and ATP6V1B1 genes associated with primary dRTA and provide insight into possible structure-function relationships.
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http://dx.doi.org/10.1093/ndt/gft216DOI Listing
August 2013

NUP98-NSD1 gene fusion and its related gene expression signature are strongly associated with a poor prognosis in pediatric acute myeloid leukemia.

Genes Chromosomes Cancer 2013 Jul 30;52(7):683-93. Epub 2013 Apr 30.

Department of Hematology/Oncology, Gunma Children's Medical Center, Shibukawa, Japan.

The cryptic t(5;11)(q35;p15.5) creates a fusion gene between the NUP98 and NSD1 genes. To ascertain the significance of this gene fusion, we explored its frequency, clinical impact, and gene expression pattern using DNA microarray in pediatric acute myeloid leukemia (AML) patients. NUP98-NSD1 fusion transcripts were detected in 6 (4.8%) of 124 pediatric AML patients. Supervised hierarchical clustering analyses using probe sets that were differentially expressed in these patients detected a characteristic gene expression pattern, including 18 NUP98-NSD1-negative patients (NUP98-NSD1-like patients). In total, a NUP98-NSD1-related gene expression signature (NUP98-NSD1 signature) was found in 19% (24/124) and in 58% (15/26) of cytogenetically normal cases. Their 4-year overall survival (OS) and event-free survival (EFS) were poor (33.3% in NUP98-NSD1-positive and 38.9% in NUP98-NSD1-like patients) compared with 100 NUP98-NSD1 signature-negative patients (4-year OS: 86.0%, 4-year EFS: 72.0%). Interestingly, t(7;11)(p15;p15)/NUP98-HOXA13, t(6;11)(q27;q23)/MLL-MLLT4 and t(6;9)(p22;q34)/DEK-NUP214, which are known as poor prognostic markers, were found in NUP98-NSD1-like patients. Furthermore, another type of NUP98-NSD1 fusion transcript was identified by additional RT-PCR analyses using other primers in a NUP98-NSD1-like patient, revealing the significance of this signature to detect NUP98-NSD1 gene fusions and to identify a new poor prognostic subgroup in AML.
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http://dx.doi.org/10.1002/gcc.22064DOI Listing
July 2013

Kasabach-Merritt phenomenon: a report of 11 cases from a single institution.

J Pediatr Hematol Oncol 2013 Oct;35(7):554-8

Departments of *Hematology/Oncology †Radiology ‡Pathology §Division of Plastic Surgery, Saitama Children's Medical Center, Magome, Saitama, Japan.

Background: Kasabach-Merritt phenomenon (KMP) is a rare condition and optimal treatments have not yet been established, especially for cases that are unresponsive to first-line therapy. We retrospectively reviewed 11 KMP cases treated over the past 13 years in our institute.

Observations: With the exception of 1 case, steroids were administered as the first-line therapy. Eight cases required second-line or third-line therapy. The effective salvage therapies include interferon (n=1), radiotherapy (n=1), and chemotherapy (n=5). One case continues to depend upon chemotherapy. Three refractory cases were therapy dependent over 1 year of age, whereas 8 were treated effectively by 6 months of age.

Conclusions: Chemotherapy seems to be the most effective therapy for steroid-resistant KMP cases.
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http://dx.doi.org/10.1097/MPH.0b013e318281558eDOI Listing
October 2013

[Unrelated cord blood transplantation in a child with very severe aplastic anemia].

Rinsho Ketsueki 2012 Dec;53(12):1997-2002

Department of Hematology, Saitama Children's Medical Center, Japan.

Recently, bone marrow transplantation from an unrelated donor has been recommended as an option for the treatment of very severe aplastic anemia (vSAA) refractory to immunosuppressive therapy (IST) in the absence of a human leukocyte antigen-matched related donor (MRD). For SAA patients with complications such as bacterial infections, prompt transplantation using either a mismatched related donor or cord blood (CB) becomes necessary. However, the former option is associated with graft-versus-host disease, whereas the latter option is associated with a more significant risk of graft failure. We report a patient with vSAA refractory to IST that was repeatedly complicated by bacterial infection. An MRD was unavailable for this patient, so we decided on emergent transplantation and successfully performed CB transplantation (CBT) using a low-dose TBI conditioning regimen. Although it may be necessary to examine more clinical cases in the future, a conditioning regimen such as that involving low-dose TBI may decrease the risk of graft failure, and CBT may become a treatment option for vSAA in the absence of a suitable donor.
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December 2012

Chronic mucocutaneous candidiasis caused by a gain-of-function mutation in the STAT1 DNA-binding domain.

J Immunol 2012 Aug 22;189(3):1521-6. Epub 2012 Jun 22.

Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.

Chronic mucocutaneous candidiasis (CMC) is a heterogeneous group of primary immunodeficiency diseases characterized by chronic and recurrent Candida infections of the skin, nails, and oropharynx. Gain-of-function mutations in STAT1 were very recently shown to be responsible for autosomal-dominant or sporadic cases of CMC. The reported mutations have been exclusively localized in the coiled-coil domain, resulting in impaired dephosphorylation of STAT1. However, recent crystallographic analysis and direct mutagenesis experiments indicate that mutations affecting the DNA-binding domain of STAT1 could also lead to persistent phosphorylation of STAT1. To our knowledge, this study shows for the first time that a DNA-binding domain mutation of c.1153C>T in exon 14 (p.T385M) is the genetic cause of sporadic CMC in two unrelated Japanese patients. The underlying mechanisms involve a gain of STAT1 function due to impaired dephosphorylation as observed in the coiled-coil domain mutations.
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http://dx.doi.org/10.4049/jimmunol.1200926DOI Listing
August 2012

RAS mutations are frequent in FAB type M4 and M5 of acute myeloid leukemia, and related to late relapse: a study of the Japanese Childhood AML Cooperative Study Group.

Int J Hematol 2012 May 10;95(5):509-15. Epub 2012 Mar 10.

Department of Hematology/Oncology, Gunma Children's Medical Center, 779 Shimohakoda, Hokkitsu, Shibukawa, Gunma, 377-8577, Japan.

Mutations in RAS are frequent in acute myeloid leukemia (AML), and are thought to contribute to leukemogenesis in a subset of patients; however, their prognostic significance has not been firmly established. One hundred and fifty-seven pediatric patients with AML were analyzed for NRAS and KRAS mutations around hot spots at codons 12, 13, and 61. Twenty-nine patients (18.5%) had an activating mutation of RAS. We found KRAS mutations to be more frequent than NRAS mutations (18/29, 62.1% of patients with RAS mutation), in contrast to previous reports (18-40%). The frequency of RAS mutation was higher in French-American-British types M4 and M5 than other types (P = 0.02). There were no significant differences in other clinical manifestations or distribution in cytogenetic subgroups, or aberrations of other genes, including KIT mutation, FLT3-ITD, and MLL-PTD, between patients with and without RAS mutations. No significant differences were observed in the 3-year overall survival and disease-free survival; however, the presence of RAS mutation was related to late relapse. The occurrence of clinical events at relatively late period should be monitored for in AML patients with mutations in RAS.
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http://dx.doi.org/10.1007/s12185-012-1033-xDOI Listing
May 2012

Identification of TRIB1 R107L gain-of-function mutation in human acute megakaryocytic leukemia.

Blood 2012 Mar 31;119(11):2608-11. Epub 2012 Jan 31.

Division of Carcinogenesis, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.

Trib1 has been identified as a myeloid oncogene in a murine leukemia model. Here we identified a TRIB1 somatic mutation in a human case of Down syndrome-related acute megakaryocytic leukemia. The mutation was observed at well-conserved arginine 107 residue in the pseudokinase domain. This R107L mutation remained in leukocytes of the remission stage in which GATA1 mutation disappeared, suggesting the TRIB1 mutation is an earlier genetic event in leukemogenesis. The bone marrow transfer experiment showed that acute myeloid leukemia development was accelerated by transducing murine bone marrow cells with the R107L mutant in which enhancement of ERK phosphorylation and C/EBPα degradation by Trib1 expression was even greater than in those expressing wild-type. These results suggest that TRIB1 may be a novel important oncogene for Down syndrome-related acute megakaryocytic leukemia.
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http://dx.doi.org/10.1182/blood-2010-12-324806DOI Listing
March 2012

CBL mutation in chronic myelomonocytic leukemia secondary to familial platelet disorder with propensity to develop acute myeloid leukemia (FPD/AML).

Blood 2012 Mar 2;119(11):2612-4. Epub 2011 Dec 2.

Department of Hematology/Oncology, Gunma Children's Medical Center, Shibukawa, Japan.

Familial platelet disorder with a propensity to develop acute myeloid leukemia (FPD/AML) is a rare autosomal dominant disease characterized by thrombocytopenia, abnormal platelet function, and a propensity to develop myelodysplastic syndrome (MDS) and AML. So far, > 20 affected families have been reported. Recently, a second RUNX1 alteration has been reported; however, no additional molecular abnormalities have been found so far. We identified an acquired CBL mutation and 11q-acquired uniparental disomy (11q-aUPD) in a patient with chronic myelomonocytic leukemia (CMML) secondary to FPD with RUNX1 mutation but not in the same patient during refractory cytopenia. This finding suggests that alterations of the CBL gene and RUNX1 gene may cooperate in the pathogenesis of CMML in patients with FPD/AML. The presence of CBL mutations and 11q-aUPD was an important "second hit" that could be an indicator of leukemic transformation of MDS or AML in patients with FPD/AML.
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http://dx.doi.org/10.1182/blood-2011-02-333435DOI Listing
March 2012

NOTCH1 mutation in a female with myeloid/NK cell precursor acute leukemia.

Pediatr Blood Cancer 2010 Dec;55(7):1406-9

Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.

A 6-year-old Japanese female was diagnosed as having myeloid/NK cell precursor acute leukemia (MNKL) using immunocytochemical analysis. The patient was treated by cord blood transplantation from an HLA 1-locus mismatched unrelated donor after chemotherapy comprising cytosine arabinoside, idarubicin, etoposide, and L-asparaginase. We detected a nonsense mutation, C7412A, resulting in S2471X, where X is a terminal codon, in the PEST domain of NOTCH1 in this patient. The presence of the NOTCH1 activating mutation in MNKL might suggest a possible role in the leukemogenesis of MNKL.
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http://dx.doi.org/10.1002/pbc.22758DOI Listing
December 2010

Mutations in the ribosomal protein genes in Japanese patients with Diamond-Blackfan anemia.

Haematologica 2010 Aug 7;95(8):1293-9. Epub 2010 Apr 7.

Department of Pediatrics, Hirosaki University Graduate School of Medicine,5 Zaifucho, Hirosaki, Aomori 036-8562, Japan.

Background: Diamond-Blackfan anemia is a rare, clinically heterogeneous, congenital red cell aplasia: 40% of patients have congenital abnormalities. Recent studies have shown that in western countries, the disease is associated with heterozygous mutations in the ribosomal protein (RP) genes in about 50% of patients. There have been no studies to determine the incidence of these mutations in Asian patients with Diamond-Blackfan anemia.

Design And Methods: We screened 49 Japanese patients with Diamond-Blackfan anemia (45 probands) for mutations in the six known genes associated with Diamond-Blackfan anemia: RPS19, RPS24, RPS17, RPL5, RPL11, and RPL35A. RPS14 was also examined due to its implied involvement in 5q- syndrome.

Results: Mutations in RPS19, RPL5, RPL11 and RPS17 were identified in five, four, two and one of the probands, respectively. In total, 12 (27%) of the Japanese Diamond-Blackfan anemia patients had mutations in ribosomal protein genes. No mutations were detected in RPS14, RPS24 or RPL35A. All patients with RPS19 and RPL5 mutations had physical abnormalities. Remarkably, cleft palate was seen in two patients with RPL5 mutations, and thumb anomalies were seen in six patients with an RPS19 or RPL5 mutation. In contrast, a small-for-date phenotype was seen in five patients without an RPL5 mutation.

Conclusions: We observed a slightly lower frequency of mutations in the ribosomal protein genes in patients with Diamond-Blackfan anemia compared to the frequency reported in western countries. Genotype-phenotype data suggest an association between anomalies and RPS19 mutations, and a negative association between small-for-date phenotype and RPL5 mutations.
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http://dx.doi.org/10.3324/haematol.2009.020826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2913077PMC
August 2010

JAK2V617F mutation-positive childhood essential thrombocythemia associated with cerebral venous sinus thrombosis.

J Pediatr Hematol Oncol 2009 Sep;31(9):678-80

Department of Pediatrics, Dokkyo Medical University School of Medicine, Tochigi, Japan.

Myeloproliferative diseases (MPDs) in childhood are quite rare. Although pediatric and adult MPDs exhibit similar hematologic findings, JAK2V617F mutations and clonality status of MPDs in the DNA of neutrophils are evaluated less frequently in children than in adults. Increased incidence of venous thrombosis at uncommon sites is associated with JAK2V617F mutation in MPDs and thrombotic complications are more common in essential thrombocythemia (ET). Here, we describe 6-year-old girl with clonal myelopoiesis and JAK2V617F-positive ET associated with cerebral venous sinus thrombosis. To our knowledge, this is the first report of pediatric monoclonal and JAK2V617F-positive ET with cerebral venous sinus thrombosis.
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http://dx.doi.org/10.1097/MPH.0b013e3181b1ec9eDOI Listing
September 2009
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