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Two Researchers from National Cancer Center on ‘Highly Cited Researchers 2025’ List
December 2, 2025
Researchers from NCC, Hiroyoshi Nishikawa of the Research Institute, and Kohei Shitara of Hospital East were listed on ‘Highly Cited Researchers 2025’ as the most frequently cited researchers in their respective fields, announced by Clarivate on November 12, 2025.
‘Highly Cited Researchers’ are those whose work are cited particularly frequently, considered the top one percent in their specific fields. 6,868 researchers from 61 countries and regions have been recognized this year.
Reference: Highly Cited Researchers--Clarivate (link to external site)
Hiroyoshi Nishikawa
Hiroyoshi Nishikawa
Award category: Immunology
Chief - Division of Cancer Immunology, Research Institute
Chief – Division of Cancer Immunology, Exploratory Oncology Research & Clinical Trial Center (EPOC)
Dr Nishikawa has studied the mechanisms of anti-tumor immune response suppression in cancer immunity. In particular, he has found that genetic abnormalities in the cancer cells themselves play a critical role in the establishment of immunosuppressive networks, including CD4-positive regulatory T (Treg) cells, and advocates the “immunogenomic cancer progression theory” and is working to realize immunogenomic precision medicine. He also found that CD8-positive killer T cells, which are important for anti-tumor immune responses, are suppressed by regulatory T cells depending on the nature of the antigen (self vs non-self) as recognized by the T cells. Furthermore, in recent years, he has elucidated the mechanism by which bacteria present in the gut (gut bacteria) influence the immune response to cancer in distant organs. These findings are extremely important for understanding not only tumor immunity, but also various immune responses such as autoimmunity, allergies, infection, and transplant-related immunity.
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Kohei Shitara
Kohei Shitara
Award Category: Clinical Medicine
Chief - Department of Gastrointestinal Oncology, Hospital East
Staff physician - Department of Experimental Therapeutics, Hospital East
Staff physician - Division of Experimental Therapeutics (Kashiwa), Exploratory Oncology Research & Clinical Trial Center (EPOC)
Dr. Shitara has been actively engaged in clinical research for the development of novel therapies for gastrointestinal cancers. In particular, he has reported the results of pivotal clinical trials of new agents for gastric cancer in The New England Journal of Medicine （NEJM）, The Lancet, Nature, Nature Medicine, Lancet Oncology, etc. as the first author or corresponding author, and these resulted in the approval of four new drugs (trastuzumab deruxtecan, nivolumab, FTD/TPI, and zolbetuximab) for gastric cancer. In 2025, he reported primary results from global phase 3 trial of trastuzumab deruxtecan for HER2 positive gastric cancer in NEJM (DESTINY-Gastric 04 study). In also, he published primary results of LEAP-15 trial in the Journal of Clinical Oncology which was conducted based on prior investigator-initiated trial. As an international coordinating investigator, he leads more than 10 global clinical trials exploring novel treatments for gastric cancer. In addition, he has spearheaded numerous investigator-initiated studies, including first-in-human trials and innovative combination therapies, as well as translational research in collaboration with both domestic and international collaborators.
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