Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本小児血液・がん学会  

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本小児血液・がん学会  

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Blood  

Therapy resistance in acute myeloid leukemia (AML) remains a major clinical obstacle, particularly because of the persistence of leukemia stem cells (LSC) capable of metabolic adaptation. Although venetoclax (Ven) inhibits oxidative phosphorylation (OXPHOS), we found that Ven-resistant LSC undergo glycolytic reprogramming to bypass OXPHOS inhibition. This metabolic shift is supported by enhanced ribosome biogenesis, which is sustained by upregulated de novo guanine nucleotide biosynthesis. Abundant guanine nucleotides suppress the impaired ribosome biogenesis checkpoint (IRBC), leading to TP53 destabilization and persistent MYC expression. The inhibition of inosine monophosphate dehydrogenases (IMPDH1/2) depletes guanine nucleotides, activates IRBC, stabilizes TP53, represses MYC, and impairs the metabolic shift to glycolysis. This metabolic rewiring disrupts LSC stemness and suppresses the reconstitution of human AML cells in xenotransplantation experiments. Notably, the suppression of LSC stemness was observed regardless of Ven resistance or the TP53 mutational status of AML cells. These findings reveal that mutation-independent TP53 inactivation is involved in resistant AML and suggest that targeting guanine nucleotide biosynthesis may offer a clinically actionable strategy to eradicate therapy-resistant LSC.

DOI： 10.1182/blood.2025030209

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1182/blood-2025-7702

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers in Hematology  

Background: Epigenetic dysregulation plays a central role in pediatric acute myeloid leukemia (AML), yet its clinical relevance remains underexplored. This study primarily aimed to elucidate the clinical effect of H3K27me3 and H3K4me3 status on pediatric acute myeloid leukemia. We evaluated the prognostic impact of H3K27me3 and H3K4me3 histone trimethylation, along with associated gene expression profiles, in pediatric AML. Methods: We retrospectively analyzed 74 children with newly diagnosed non-FAB M3 and non-Down syndrome AML in a prolonged cohort in Japan. Bone marrow immunohistochemistry assessed H3K27me3 and H3K4me3 expression levels. RNA sequencing was successfully performed on sorted leukemic blasts in six representative cases, owing to limited sample availability. Chemoresistance and epigenetic modulation were evaluated in AML cell lines treated with GSK-J4, a histone demethylase inhibitor. Results: High H3K27me3 expression at diagnosis was significantly associated with superior overall and event-free survival over three years (OS HR 8.0; EFS HR 5.0; both p < 0.01). H3K4me3 levels at diagnosis showed no prognostic impact. Among 14 KMT2A-rearranged cases, all six patients with high H3K27me3 achieved a long-term first remission (median follow-up: 10 years), whereas those with low expression had higher relapse rates. Transcriptomic analysis revealed upregulation of HOXA9, and HOXA-cluster genes and downregulation of ABCB1, in low H3K27me3 samples. In vitro, GSK-J4 increased H3K27me3 and suppressed HOXA9 expression in KG-1 cells, enhancing sensitivity to cytarabine. Conclusion: Low H3K27me3 expression defines a poor-risk group in pediatric AML, potentially via HOXA9-driven dysregulation. H3K27me3 may serve as a prognostic biomarker and potential therapeutic target.

DOI： 10.3389/frhem.2025.1668408

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Language：English   Publisher：Pediatric Blood and Cancer  

Programs allowing access to investigational drugs and off-label drug use for serious diseases have often been applied to pediatric cancers. A clinical study conducted under the Japanese “Patient-Proposed Healthcare Services” evaluated the efficacy and safety of dabrafenib plus trametinib in children with BRAF V600 mutant glioma (jRCTs071210071). This study successfully provided unapproved and off-label medications to four enrolled patients, two with low-grade glioma and two with high-grade glioma (median age: 10.5 years), until regulatory approval. The timeframe and data collection from such access programs need to be optimized for pediatric patients in accordance with the healthcare system of each nation.

DOI： 10.1002/pbc.31510

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Early Human Development  

Background: Many studies have indicated an association between maternal occupational exposure to hazardous agents, such as anticancer drugs and ionizing radiation, and an increased risk of adverse pregnancy outcomes, including stillbirths or miscarriages and physical abnormalities in offspring. However, the effects of recent advancements in protective measures to reduce these risks have not been clarified. Aim To investigate the current impact of parental occupational exposure to anticancer drugs and ionizing radiation on stillbirths or miscarriages as well as physical abnormalities under the circumstances of the developed safety protocols. Methods: This cohort study utilized The Japan Environment and Children's Study dataset, which included 96,606 fetuses born between January 2011 and March 2014. This study focused on the association between occupational exposure to these agents during pregnancy and the incidence of stillbirths or miscarriages and physical abnormalities in offspring, employing Poisson regression models for adjusted relative risk. Results: From the study population, 471 cases of stillbirths or miscarriages and 4493 infants with physical abnormalities were identified. Fisher's exact tests indicated no significant differences in fetal loss or physical abnormalities between the exposure groups. A multivariable analysis also found no significant association between maternal exposure to anticancer drugs and ionizing radiation and these adverse outcomes. Conclusion: Under improved safety measures, maternal occupational exposure to anticancer drugs and ionizing radiation does not significantly affect the occurrence of stillbirths or miscarriages and physical abnormalities in offspring. These findings highlight the critical role of current safety practices and indicate lower reproductive risks with proper precautions.

DOI： 10.1016/j.earlhumdev.2025.106195

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Language：English   Publisher：Pediatric Research  

Background: Healthcare workers are often exposed to hazardous agents and are at risk for adverse health consequences that affect not only themselves but also their infants. This study aimed to examine whether such occupational exposure increased the risk of childhood cancer in offspring. Methods: We used the dataset of the Japan Environment and Children’s Study, a nationwide birth cohort involving over 100,000 mother–child pairs. Information was obtained via successive questionnaires that were completed until the child turned 1 year of age. The parents were asked whether they occupationally handled medical agents during pregnancy. Results: A total of 26 infants developed neoplasms: neuroblastoma, leukemia, and brain tumor. The incidence of neuroblastoma was significantly higher in infants whose mothers were exposed to radiation (3/2142: 140.1 per 100,000 population) than in those who were not (12/90,384: 13.3 per 100,000 population). Multivariable regression analyses revealed a close association between maternal irradiation and the development of neuroblastoma (adjusted incident rate ratio: 10.68 [95% confidence interval: 2.98‒38.27]). Conclusions: The present study demonstrated, for the first time, a potential association between maternal occupational exposure and the occurrence of neuroblastoma in offspring. Further studies involving the large pediatric cancer registries are needed to confirm these preliminary results. Impact: Healthcare workers are often exposed to hazardous agents and are at risk for adverse health consequences that affect not only themselves but also their infants. This study examined the association between such occupational exposure and offspring’s cancers that developed until the age of 1 year. Maternal exposure to ionizing radiation was associated with infantile neuroblastoma in offspring. Further studies involving the large pediatric cancer registries are needed to confirm these preliminary results.

DOI： 10.1038/s41390-021-01634-z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Pediatric Blood and Cancer  

Background: Veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is a life-threatening complications of hematopoietic cell transplantation (HCT). Methods: We studied the impact of early defibrotide (DF) therapy on the outcomes of pediatric patients with VOD/SOS after transplantation, focusing on recent immunotherapies. A total of 111 pediatric patients who underwent HCT for malignant disease between February 2017 and March 2023 at Kyushu University Hospital were included. Results: Among 111 patients of less than 20 years of age who underwent HCT for malignancy at a single institution between 2017 and 2023, VOD/SOS occurred in 25 (23%) patients. VOD/SOS developed more frequently in the post-DF era (2020–2023, n = 58) than in the pre-DF era (31% vs. 13%, p =.04). The proportion of patients with relapsed/refractory acute lymphoblastic leukemia (ALL) was higher in the post-DF era than in the pre-DF era (44% vs. 8%, p =.04). Early DF therapy that was started at two European Society for Blood and Marrow Transplantation diagnostic criteria reduced the severity of VOD/SOS (p <.01) in comparison to non-early therapy started at less than two criteria. A multivariate analysis indicated that a history of cytokine release syndrome (odds ratio [OR] = 10.4, p =.01) and juvenile myelomonocytic leukemia (OR = 8.98, p =.04), but not an endothelial activation and stress index (EASIX) score of greater than 0.85, were independent risk factors for VOD/SOS. Conclusions: Early DF therapy improves the severity and survival outcomes of post-transplant VOD/SOS in children. However, its incidence is increasing in the era of immunotherapy for progressive diseases.

DOI： 10.1002/pbc.31331

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Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本血液学会-東京事務局  

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

Immunomodulatory drugs (IMiDs) are key drugs for treating multiple myeloma and myelodysplastic syndrome with chromosome 5q deletion. IMiDs exert their pleiotropic effects through the interaction between cell-specific substrates and cereblon, a substrate receptor of the E3 ubiquitin ligase complex. Thus, identification of cell-specific substrates is important for understanding the effects of IMiDs. IMiDs increase the risk of thromboembolism, which sometimes results in fatal clinical outcomes. In this study, we sought to clarify the molecular mechanisms underlying IMiDs-induced thrombosis. We investigated cereblon substrates in human megakaryocytes using liquid chromatography–mass spectrometry and found that thrombospondin-1 (THBS-1), which is an inhibitor of a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13, functions as an endogenous substrate in human megakaryocytes. IMiDs inhibited the proteasomal degradation of THBS-1 by impairing the recruitment of cereblon to THBS-1, leading to aberrant accumulation of THBS-1. We observed a significant increase in THBS-1 in peripheral blood mononuclear cells as well as larger von Willebrand factor multimers in the plasma of patients with myeloma, who were treated with IMiDs. These results collectively suggest that THBS-1 represents an endogenous substrate of cereblon. This pairing is disrupted by IMiDs, and the aberrant accumulation of THBS-1 plays an important role in the pathogenesis of IMiDs-induced thromboembolism.

DOI： 10.1182/bloodadvances.2023010080

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

Occupational exposure to medical agents and ionizing radiation has been suggested as a possible risk factor for childhood cancer. However, the relationship between such exposure and pediatric malignant neoplasms has not yet been comprehensively studied. This cohort study aimed to investigate the association between parental occupational exposure to hazardous medical agents or ionizing radiation and the risk of childhood cancer in offspring. Data from a large birth cohort in Japan, which included 104 062 fetuses, were analyzed. The primary outcome was the development of leukemia or brain tumors diagnosed by community physicians during the first 3 years after birth. Exposure factors were medical agents, including anticancer agents, ionizing radiation, and anesthetics, handled by mothers during pregnancy or by fathers for 3 months before conception. The incidence of leukemia, but not of brain tumors, was higher in mothers exposed to anticancer drugs. Multivariable regression analysis showed that maternal exposure to anticancer drugs was associated with an increased risk of leukemia in offspring older than 1 year (adjusted relative risk, 7.99 [95% confidence interval, 1.98-32.3]). Detailed information obtained from medical certificates of patients with identified leukemia revealed no infant leukemia but acute lymphoblastic leukemias in the exposed group. Our findings suggest that maternal occupational exposure to anticancer drugs may be a potential risk factor for acute lymphoblastic leukemia in offspring older than 1 year. Effective prevention methods may be necessary to prevent maternal exposure to anticancer drugs and to reduce the risk of childhood malignant neoplasms.

DOI： 10.1182/blood.2023021008

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Language：English   Publisher：Pediatric Blood and Cancer  

DOI： 10.1002/pbc.29915

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Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本小児血液・がん学会  

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：(一社)日本血液学会-東京事務局  

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