Bio
Dr. Watanabe is Professor Emeritus the University of Tokyo, and currently a Professor at the Department of Hematology/Oncology, at the Faculty of Medicine of St Marianna University. His research interests focus on the virology of HTLV-1, and pathophysiology of diseases caused by HTLV-1. He has contributed progress of understanding the mechanisms of malignant transformation of HTLV-1 infected T cells, which lead to clinical introduction of a novel epigenetic drug, Valemetostat. He has contributed to establishing biomarkers of risk evaluation of ATL development. He has also contributed advances of epidemiology of HTLV-1 in Japan. He has published more than 250 original papers and reviews, including those of Nature, Nature Genetics, New Eng J Med, Lancet, Lancet Inf Dis, Cancer Cell, Cell Report, PNAS, etc. He is the President of Japanese Association of HTLV-1 and associated Diseases (JSHAD), Past President of International Retrovirology Association (IRVA). He has been the Chairperson of the HTLV-1 Countermeasures Promotion Council, Japanese Ministry of Health, Labour and Welfare since 2011.

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Current Status of ATL Clinical Practice and Treatment in Japan

Bio
Dr. Utsunomiya, MD, PhD, serves as Honorable Director of Imamura General Hospital, Director of Clinical Research Center, and Director of the HTLV-1 Research Center (2018–present). Since the discovery of ATL in 1977, he has been engaged in clinical research on ATL as a hematologist. His work includes analyzing ATL clinical manifestations, conducting treatment development research through the Japan Clinical Oncology Group-Lymphoma Study Group, and developing hematopoietic stem cell transplantation using non-myeloablative conditioning regimens for elderly patients with aggressive ATL. In new drug development, he participated in clinical trials for mogamulizumab, lenalidomide, tucidinostat, and valemetostat, contributing to their approval in Japan. He also participates in a prospective cohort study on HTLV-1, the causative virus of ATL (Joint Study on Predisposing Factors of ATL Development), and in a research group investigating the reality of horizontal transmission and prevention strategies. He is now a member of multiple research projects on HTLV-1/ATL supported by the Japan Agency for Medical Research and Development (AMED) (Project Numbers: 25fk0108671h0003, 25ck0106789h0003).

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HTLV-1 Persistence: A Virological Perspective

Bio
Yorifumi Satou, MD, PhD is a virus researcher at Kumamoto University whose work centers on HTLV-1 immunovirology and the pathogenesis of adult T-cell leukemia/lymphoma (ATL). He integrates molecular virology with human immunology to explain how persistent retroviral infection reshapes T-cell function and drives disease. A defining thread of his research is the characterization of the HTLV-1 antisense gene HBZ and its immunobiological consequences. Foundational studies in PNAS (2006) and PLoS Pathogens (2011) delineated HBZ expression and function, establishing it as a driver of infected-cell persistence and a rational target for immune and therapeutic interventions. Satou has also advanced the concept of intragenic proviral regulation, demonstrating that HTLV-1 modulates its transcriptional landscape through internal regulatory elements rather than relying solely on the canonical long terminal repeat (LTR). Milestone papers in PNAS (2016), Nature Communications (2022), and Nature Microbiology (2025) mapped these intragenic programs and clarified how they govern latency, reactivation, and tissue-specific expression—insights that now underpin strategies to measure and modulate proviral activity in vivo. Bridging mechanism to disease, his team showed that ATL cells are profoundly activated T cells, not merely transformed quiescent lymphocytes (JCI, 2021). This reframed ATL as a malignancy entwined with chronic T-cell activation, with implications for immunometabolic targeting, exhaustion pathways, and rational immunotherapy design. Satou mentors trainees and collaborates across Japan and internationally, applying single-cell readouts, high-parameter cytometry, and spatial profiling to connect proviral control with host immunity. By uniting HBZ biology, intragenic regulation, and T-cell activation states, his program charts actionable routes to improved diagnostics and treatments for HTLV-1–associated diseases.

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Predicting the Development of ATL in HTLV-Carriers

Bio
Aileen trained as an immunologist at Trinity College Dublin. After completing her PhD, Aileen joined Charles Bangham’s lab in Imperial College to investigate the T cell-mediated immune response to HTLV. During her time there, she also developed methods to identify clonally expanded ATL cells in peripheral blood, and joined Graham Taylor’s laboratory in 2017 to develop her method into a diagnostic test to detect and quantify ATL clones. Using this test, she showed that ATL-like clones circulate in the peripheral blood in the premalignant, asymptomatic stage of ATL. In 2022 Aileen was appointed as a lecturer at Imperial College, and established a research group that focuses on understanding the natural history of ATL development.

Bio
Dr Rosadas is a research fellow at the department of infectious disease, Imperial College London. She is keen to support improving access to diagnostics and to help advancing the public health response to neglected infections, especially focusing on HTLV. She has been working extensively with the Brazilian Ministry of Health, the Pan American Health Organization and the World Health Organization to support evidence-based public health response. She is passionate about science communication and community engagement and has co-founded a social media platform, HTLV Channel, to increase awareness about this virus, share research findings with the community, empower civil society and promote inter-sectoral collaboration.

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Towards the Clinical Validation of the Viral Clonality Evenness (VCE) Index: A Novel Prognostic Biomarker for Adult T-cell Leukemia

Bio
Anne Van den Broeke, DVM, PhD, leads the Viral Oncogenesis Research Unit at the Institut Jules Bordet Cancer Center - HUB in Brussels, Belgium, and heads the BLV/HTLV-1 Genomics Team within the Unit of Animal Genomics at the GIGA Research Institute, University of Liège. Her research focuses on deltaretrovirus-induced proliferative diseases in humans (Human T-cell leukemia virus type 1, HTLV-1, and Adult T-cell leukemia/lymphoma, ATL) and in corresponding animal models (Bovine Leukemia Virus, BLV, in cattle and sheep). Dr. Van den Broeke also holds a Visiting Professorship at the Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Canada, which provides access to animal facilities for in vivo studies in outbred/domestic animal models of cancer. Her current work in large-animal models focuses on single-cell genomics and in vivo tracking of barcode-labeled viruses using the BLV ovine model of leukemia to advance fundamental research in virus-mediated oncogenesis. On the translational side, she established an active collaboration with the Joint Study on Predisposing Factors for ATL Development (JSPFAD), a nationwide cohort in Japan, aimed at implementing a diagnostic/prognostic biomarker developed by her team to stratify risk among HTLV-1 asymptomatic carriers. Since 2024, she has also been a member of the International Retrovirus Association (IRVA) HTLV-1 Prognostic Biomarker Working Group, reflecting her commitment to advancing the understanding and clinical management of HTLV-1–associated diseases.

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Antivirals and RNA Vaccines to Prevent Human T-lymphotropic Retrovirus (HTLV-1) Infection and Disease

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Damian Purcell is a tenured Professor of Virology at the University of Melbourne.  He obtained a PhD from the University of Melbourne in 1987 and was a postdoctoral fellow at the NIAID with Dr Malcolm Martom, in Bethesda from 1989 - 94 working on human retroviruses HIV and HTLV with funding from Australia’s NHMRC. He returned to the Burnet Institute in Melbourne in 1995 and in 2001 he took a faculty position at the Department of Microbiology and Immunology at the University of Melbourne. He is now based at the Doherty Institute where he leads the Molecular Virology Laboratory and is Head of Industry Partnerships. He is a Past President and Fellow of the Australasian Virology Society, Governing Councillor of the International Retrovirology Association, Member of the Scientific Leadership Committee of the Global Virus Network and President of the RNA4Health Society in the Asia Pacific.

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From Genomic and Epigenomic Maps to Medicines in Adult T-Cell Leukemia/Lymphoma

Bio
Makoto Yamagishi, PhD, is an Associate Professor at the Graduate School of Frontier Sciences, The University of Tokyo (2023–present), where he directs the Laboratory of Viral Oncology and Genomics and currently mentors 18 graduate students. He pioneered the first comprehensive, multi-omics portrait of adult T-cell leukemia/lymphoma (ATL), delineating genomic, epigenomic, transcriptomic, and microRNA dysregulation and elucidating NF-κB activation mechanisms (Cancer Cell, 2012). His group mapped genome-wide histone marks to reveal aberrant EZH1/2-mediated H3K27me3 accumulation (Blood, 2016), uncovered epigenetic silencing of many tumor suppressor genes, activation of signaling networks (e.g., NF-κB, Hedgehog), and identified defects in splicing and translation. He developed a high-depth sequencing panel (PNAS, 2020) and, with single-cell analyses, resolved clonal evolutionary trajectories and mutation landscape in ATL (Nat Commun, 2021). In collaboration with Daiichi Sankyo, he co-developed the first-in-class dual EZH1/2 inhibitor valemetostat, advancing from preclinical proof-of-concept (Cell Rep, 2019) to regulatory approval in Japan (2022). Beyond ATL, his team also defined the distinct transcriptomic pathology of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and advanced therapeutics with successful patenting. His lab’s Nature paper (2024) delivered the first demonstration in patients of how the dual EZH1/2 inhibitor valemetostat - a histone methylation-targeted therapy - acts and how resistance emerges with prolonged dosing, providing foundational evidence for next-generation epigenomic treatments.

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Multiomics of HAM/TSP and Implications for Drug Discovery

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He received his M.D. (1993) and Ph.D. (1997) from Kagoshima University, and completed a postdoctoral fellowship at the NIH in 2003. Since 2008, he has led the Department of Rare Diseases Research at St. Marianna University School of Medicine, where he has also served as Professor of Neurology since 2020.