Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Society of Hematology  

Abstract

We investigated genome-wide DNA methylation patterns in 64 pediatric patients with acute myeloid leukemia (AML). Based on unsupervised clustering with the 567 most variably methylated cytosine guanine dinucleotide (CpG) sites, patients were categorized into 4 clusters associated with genetic alterations. Clusters 1 and 3 were characterized by the presence of known favorable prognostic factors, such as RUNX1-RUNX1T1 fusion and KMT2A rearrangement with low MECOM expression, and biallelic CEBPA mutations (all 8 patients), respectively. Clusters 2 and 4 comprised patients exhibiting molecular features associated with adverse outcomes, namely internal tandem duplication of FLT3 (FLT3-ITD), partial tandem duplication of KMT2A, and high PRDM16 expression. Depending on the methylation values of the 1243 CpG sites that were significantly different between FLT3-ITD+ and FLT3-ITD− AML, patients were categorized into 3 clusters: A, B, and C. The STAT5-binding motif was most frequently found close to the 1243 CpG sites. All 8 patients with FLT3-ITD in cluster A harbored high PRDM16 expression and experienced adverse events, whereas only 1 of 7 patients with FLT3-ITD in the other clusters experienced adverse events. PRDM16 expression levels were also related to DNA methylation patterns, which were drastically changed at the cutoff value of PRDM16/ABL1 = 0.10. The assay for transposase-accessible chromatin sequencing of AMLs supported enhanced chromatin accessibility around genomic regions, such as HOXB cluster genes, SCHIP1, and PRDM16, which were associated with DNA methylation changes in AMLs with FLT3-ITD and high PRDM16 expression. Our results suggest that DNA methylation levels at specific CpG sites are useful to support genetic alterations and gene expression patterns of patients with pediatric AML.

DOI： 10.1182/bloodadvances.2021005381

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Summary

KIT D816V mutation within exon 17 has been particularly reported as one of the poor prognostic factors in pediatric acute myeloid leukemia (AML) with RUNX1‐RUNX1T1. The exact frequency and the prognostic impact of KIT D816V minor clones at diagnosis were not examined. In this study, the minor clones were examined and the prognostic significance of KIT D816V mutation in pediatric patients was investigated. Consequently, 24 KIT D816V mutations (7.2%) in 335 pediatric patients were identified, and 12 of 24 were only detected via the digital droplet polymerase chain reaction method. All 12 patients were confined in core binding factor (CBF)‐AML patients. The 5 year event‐free survival of the patients with KIT D816V mutation was significantly inferior to those without KIT D816V mutation (44.1% [95% confidence interval (CI), 16.0%–69.4%] vs. 74.7% [95% CI, 63.0%–83.2%] P‐value = 0.02, respectively). The 5 year overall survival was not different between the two groups (92.9% [95% CI, 59.0%–NA vs. 89.7% [95% CI, 69.6%–96.8%] P‐value = 0.607, respectively). In this study, KIT D816V minor clones in patients with CBF‐AML were confirmed and KIT D816V was considered as a risk factor for relapse in patients with RUNX1‐RUNX1T1‐positive AML.

DOI： 10.1111/bjh.17569

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/bjh.17569

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) with both inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and monosomy 7 defines an extremely aggressive myeloid cancer whose molecular pathogenesis and optimal therapeutic strategy still remain unclear. We established a new MDS/AML cell line, YCU‐AML1, and its patient‐derived xenograft (PDX) model from a high‐risk MDS patient who later transformed into AML harboring both t(3;3)(q21;q26.2) and monosomy 7. YCU‐AML1 cells propagated in co‐culture system with stromal cells in granulocyte macrophage colony‐stimulating factor (GM‐CSF)‐dependent manner. CD34⁺ bone marrow cells derived from our PDX model showed high EVI1 and low GATA2 expression. Moreover, mutational profile of our MDS/AML model was consistent with recently published mutational spectrum of myeloid malignancies with inv(3)/t(3;3). These data suggest that YCU‐AML1 cells and its MDS/AML model strongly mimics a high‐risk human myeloid cancer with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) and monosomy 7 in terms of both clinical phenotype and molecular basis. We believe our model can be used as a feasible tool to further explore molecular pathogenesis and novel treatment strategy of high‐risk MDS/AML with t(3;3)(q21;q26.2) and monosomy 7.

DOI： 10.1097/hs9.0000000000000469

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ovid Technologies (Wolters Kluwer Health)  

Primary central nervous system lymphoma (PCNSL) is a rare and aggressive type of extranodal non-Hodgkin lymphoma that carries an unsatisfactory prognosis. Treating refractory PCNSL is challenging because of resistance to conventional cytotoxic and intrathecal chemotherapies. Therefore, novel therapeutic approaches are needed. Here, we report a 12-year-old boy with CD20-positive PCNSL, which was refractory to combination chemotherapy and intravenous rituximab. However, the patient achieved complete remission after repeated intraventricular rituximab administration. The results of this case indicate that intraventricular rituximab is an effective option to treat refractory PCNSL in children.

DOI： 10.1097/mph.0000000000001291

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Abstract

Infant acute lymphoblastic leukemia with lysine (K)‐specific methyltransferase 2A (KMT2A) rearrangements usually has a poor prognosis regardless of the fusion partners of KMT2A. However, the prognosis of pediatric acute myeloid leukemia (AML) with KMT2A rearrangements depends on its translocation partners. We herein report the case of a 9‐month‐old boy with a KMT2A‐USP2 fusion, which required diagnosis by whole transcriptome sequencing after the failure of detection of known translocation partners by conventional screening approaches. As this first report of a patient with AML with a KMT2A‐USP2 fusion illustrates, identification of the partners in all patients with KMT2A‐rearranged AML is critical to elucidate the outcomes associated with specific rearrangements and to develop appropriate treatment strategies. Moreover, development of additional methods to detect specific translocation partners of KMT2A and leukemia‐specific targeting drugs is important to improve further the outcomes of KMT2A‐rearranged AML.

DOI： 10.1002/gcc.22751

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/gcc.22751

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

In the revised World Health Organization classification 2016, anaplastic pleomorphic xanthoastrocytoma (PXA) has been newly defined as a variant of the PXA entity. Furthermore, some anaplastic PXA were reported to have extremely poor prognosis which showed a type of pediatric glioblastoma (GBM) molecular profile. Recent integrated molecular classification for primary central nervous system tumors proposed some differences between histological and molecular features. Herein, in a genome‐wide molecular analysis, we show an extreme aggressive anaplastic PXA that resulted in a pediatric GBM molecular profile. A full implementation of the molecular approach is the key to predict prognosis and decide the treatment strategy for anaplastic PXA.

DOI： 10.1111/cas.13903

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/cas.13903

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10014-017-0297-5

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Other Link： http://link.springer.com/content/pdf/10.1007/s10014-017-0297-5.pdf

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Medical Association of Yokohama City University  

Scopus

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