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Yasuhiro SAKAI

  (酒井 康弘)

Profile Information

Affiliation
Associate Professor, Department of Tumor Pathology, Hamamatsu University School of Medicine
Visiting Associate Professor, Department of Joint Research Laboratory of Clinical Medicine, Fujita Health University School of Medicine
Degree
M.D.(Apr, 2009)
Ph.D. in Medical Science(Mar, 2014, Shinshu University Graduate School of Medicine)
Researcher number
20754394
ORCID ID
 https://orcid.org/0000-0001-7210-9249
J-GLOBAL ID
201801008077367216
Researcher ID
JWO-5020-2024
researchmap Member ID
7000023712

Licenses and Qualifictions

M.D. (Japan); M.T. (Japan); Qualification of Autopsy (Japan)
Ph.D. in Medical Science (Shinshu University)

Certified Pathologist (Japanese Medical Specialty Board / Japanese Society of Pathology);
Certified Clinical Laboratory Physician and Qualified Clinical Laboratory Managing Physician (Japanese Society of Laboratory Medicine);
Certified Molecular Pathologist (Japanese Society of Pathology);
Board Certified Fellow and Trainer (Japanese Society of Clinical Cytology)
Certified Clinical Chemist (Japanese Society of Clinical Chemistry)

ICDP-UEMS International Board Certification in Dermatopathology (International Committee for Dermatopathology / European Union of Medical Specialists);
Internatinal Board of Cytopathology (Internatinal Academy of Cytology)

Hazardous Materials Engineer (Class A);
Operation Chief of Specified Chemical Substances and Tetra-Alkyl Lead, etc.;
Operation Chief of Organic Solvent;
Operation Chief of Lead

Biography

SAKAI Yasuhiro, MD, PhD, FIAC, is a dermatopathologist certified by the ICDP-UEMS International Board Certification in Dermatopathology. He also holds Japanese board certifications as a Anatomic Pathologist, Clinical Laboratory Physician (Clinical Pathologist), Cytopathologist, Molecular Pathologist, and Clinical Chemist. Additionally, he holds the International Board of Cytopathology, recognized by the International Academy of Cytology (IAC).

Dr. Sakai graduated from Shinshu University School of Medicine in 2009 and obtained his medical license that same year. He earned his Doctor of Philosophy (PhD) from the Shinshu University Graduate School of Medicine in 2014. To date, he has received several prestigious awards, including the Japanese Society of Pathology’s Centennial Anniversary Award for Young Scientists in 2013, the Incitement Award from the same society in 2022, and the Young Investigator Award from the Japanese Society of Laboratory Medicine in 2024.

Dr. Sakai is actively engaged in dermatopathological diagnosis and immunopathology research. His primary research interests include the dynamics of immune responses and tumorigenesis associated with immunological DNA repair factors. He is also investigating the potential application of immunologic signaling molecules as valuable diagnostic markers in pathology.

Research Interests

 6

Research Areas

 7

Research History

 8
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Education

 3

Committee Memberships

 13
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Awards

 8
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Papers

 65
  • Yasuhiro Sakai, Taku Kato, Midori Saito, Michiko Osawa, Kazuya Shinmura, Koichi Seto, Kuniaki Saito, Hiroyasu Ito
    Clinica Chimica Acta, 579 120664, Jan 15, 2026  Peer-reviewedLead authorCorresponding author
    Background and aims: Capillary Cup® is a novel finger-stick blood collection device equipped with separation float technology to effectively isolate plasma and blood cell layers. This study aimed to evaluate its analytical equivalence compared to venipuncture sampling in clinical chemistry, complete blood count, and hemoglobin A1c testing. Methods: Blood samples were collected from 63 healthy participants for clinical chemistry and hemoglobin A1c tests and 67 for complete blood count tests. Discrepancies between the Capillary Cup® and venipuncture sampling results were analyzed using the 2025 Clinical Laboratory Improvement Amendments (CLIA) acceptance limits and total allowable error (TEA) thresholds. Results: The Capillary Cup® samples showed strong linear correlations with venipuncture samples across proteins, transaminases, kidney function markers, lipids, C-reactive protein, blood cell and platelet counts, white blood cell differentials, hemoglobin, hematocrit, and Wintrobe's indices (r = 0.740–0.999, P < 0.0001). Hemoglobin A1c was accurately measured alongside other clinical chemistry markers in a single kit (r = 0.976, P < 0.0001). All values met the 2025 CLIA acceptance limits, and most also met the TEA thresholds. Minor deviations were observed for creatinine, triglycerides, and C-reactive protein, as well as for platelet counts—potentially affected by activation and aggregation—but all remained within acceptance limits and demonstrated preserved linearity. Conclusions: The Capillary Cup® provides analytically equivalent results to venipuncture for all tested parameters. It is easy to use, reduces waste, and is a potential alternative for at-home health monitoring, addressing challenges in venous access, and reducing iatrogenic blood loss risk in clinical practice.
  • Ryosuke Miyazaki, Hideya Kawasaki, Hisami Kato, Isao Ohta, Rei Ishikawa, Katsuhiro Yoshimura, Hidetaka Yamada, Yasuhiro Sakai, Hiroyuki Suzuki, Miki Sugita, Yoshiko Watanabe, Kazuya Masumoto, Kazuya Shinmura
    Journal of Dental Research, in press, 2026  Peer-reviewed
  • Tatsuya Ando, Kouhei Sakurai, Masato Hoshi, Hiroyuki Tezuka, Yasuhiro Sakai, Taku Kato, Hiroyasu Ito
    Immunobiology, 230(6) 153119, Nov 17, 2025  Peer-reviewed
    The effectiveness of immune checkpoint inhibitors is diminished by the presence of myeloid-derived suppressor cells (MDSCs). Recent studies indicate that the NLR family pyrin domain-containing 3 (NLRP3) inflammasome regulates MDSC function, thereby reducing the efficacy of immune checkpoint inhibitors. However, the specific mechanism by which NLRP3 expression induces the immunosuppressive effects in MDSCs remains unclear. Here, we demonstrate that the adenosine triphosphate (ATP)–NLRP3 inflammasome axis enhances the immunosuppressive effects of MDSCs. We found that ATP increases the mRNA levels of immunosuppressive molecules in MDSCs, leading to the suppression of T cell proliferation. Additionally, we showed the efficacy of a novel immune checkpoint therapy that combines an ATP receptor inhibitor (P2X7 receptor inhibitor), an NLRP3 inhibitor, and an anti-PD-L1 antibody (Ab). This combination treatment significantly inhibited tumor growth compared to treatment with only the NLRP3 inhibitor and anti-PD-L1 Ab. These results suggest that the ATP–NLRP3 axis enhances the immunosuppressive effect of MDSCs. In conclusion, this study elucidates the mechanism through which MDSCs acquire immunosuppressive functions, potentially informing the development of novel cancer immunotherapies.
  • Shin-ya Katsuragi, Yuri Sakano, Isao Ohta, Hisami Kato, Rei Ishikawa, Hirofumi Watanabe, Ryosuke Miyazaki, Katsuhiro Yoshimura, Hidetaka Yamada, Yasuhiro Sakai, Yusuke Inoue, Yusuke Takanashi, Keigo Sekihara, Kazuhito Funai, Yoshiro Otsuki, Hideya Kawasaki, Kazuya Shinmura
    Diagnostics, 15(10) 1298, May 21, 2025  Peer-reviewed
    Background/Objectives: Differentiating thoracic malignant tumors, such as epithelioid malignant pleural mesothelioma (EMPM) and non-small-cell lung carcinoma (NSCLC), primarily comprising lung adenocarcinoma (LAC) and lung squamous cell carcinoma (LSCC), remains a challenge in routine pathological diagnosis. This study aimed to evaluate whether podoplanin (PDPN) immunohistochemistry combined with scanning electron microscopy (SEM) using the NanoSuit-correlative light and electron microscopy (CLEM) methods could serve as a reliable tool for distinguishing these thoracic malignancies. Methods/Results: Initially, PDPN expression was assessed by immunohistochemical analysis in 11 EMPM, 100 LAC, and 23 LSCC cases. PDPN positivity was predominantly observed in the cell membrane and was significantly more frequent in EMPM (100%) than in LAC (2%; p &lt; 0.0001) or LSCC (43.5%; p = 0.0018). Subsequently, field emission–SEM (FE-SEM) observations of PDPN-positive sites on immunohistochemical slides, conducted using the NanoSuit-CLEM method, revealed distinctive ultrastructural features. EMPM exhibited densely packed, elongated microvilli, whereas such structures were absent in LAC and LSCC. Furthermore, analysis of thick-cut sections (20 μm) demonstrated extensive microvilli coverage characteristic of EMPM. Conclusions: These findings suggest that the combined approach of PDPN immunohistochemistry and FE-SEM observation of PDPN-positive sites, using the NanoSuit-CLEM method, constitutes an effective diagnostic strategy for enhancing the accuracy of distinguishing EMPM from NSCLCs.
  • Kanata Kojima, Kouhei Sakurai, Tatsuya Ando, Yasuhiro Sakai, Mako Ochiai, Taku Kato, Hiroyasu Ito
    Medical Molecular Morphology, in press, 2025  Peer-reviewed
    Prospero homeobox protein 1 (PROX1) is aberrantly expressed in tumors, including neuroendocrine neoplasms (NENs); however, the detailed expression pattern remains elusive. This study aimed to immunohistochemically assess PROX1 expression. Immunohistochemistry (IHC) for PROX1 was performed on tissue microarrays of normal tissues (n = 107), NENs (n = 152) (small cell lung carcinoma [SCLC], lung carcinoid [LC], gastroenteropancreatic-NEN [GEP-NEN], esophageal neuroendocrine carcinoma [ENEC], medullary thyroid carcinoma [MTC], neuroblastoma [NB], and pheochromocytoma [PHEO]), and non-NENs (n = 469). In normal tissues, PROX1 was expressed in lymphatic endothelial cells and a subset of epithelial cells in the gastrointestinal tract and the distal convoluted tubules. In NENs, the positive expression was observed in the nucleus of tumor cells in 19/26 SCLC (73.1%), 13/16 LC (81.3%), 10/15 GEP-NEN (66.7%), 2/2 ENEC (100%), 17/43 MTC (39.5%), 1/25 NB (4.0%), and 0/25 PHEO (0%). Although PROX1 was negative in many non-NENs, our analysis revealed high expression in certain cases with medulloblastoma and one case with juvenile granulosa cell tumor. PROX1 was expressed in specific cases with epithelial NENs and some cases with non-NENs. Analysis of PROX1 should provide insights into the molecular characteristics of distinct tumors.
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Books and Other Publications

 7
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Presentations

 74

Teaching Experience

 13
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Professional Memberships

 13
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Research Projects

 14
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Academic Activities

 1
  • Planning, Management, etc., Supervision (editorial), Planning/Implementing academic research
    Working group regarding the formulation of the AI (artificial intelligence) guideline, Japanese Society of Pathology, Apr 10, 2019 - Jul 12, 2022
    近年，さまざまな分野で AI（artificial intelligence）技術を駆使したソフトウェアやそれを実装した機器が実用的に使用されるようになってきた。それらは医療分野でも急速に普及し，画像診断に限っても，放射線画像や内視鏡画像の解析に商品化された AI が医療現場で使用されるようになってきた。病理診断の分野でも今後の普及は想像に難くない。病理医あるいは他の医療人の間には，AI 技術が進歩すればやがては病理医が不要になるとの憶測も流れている。しかし，本会（日本病理学会）は，「人工知能 AI と病理医について」と題したステートメントを市民に向けてホームページに公開し，「病理診断も AI が行うので病理医は必要がなくなる，と誤った情報が一部で流れています。日本病理学会では，将来病理医がAI を使うことがあっても，AI は病理医にとってかわるものではないことをここに明確にします。」と明言している。本手引きは，病理診断に有用な AI を開発し，また病理医が適切にAI を使いこなすために必要な情報を提供することを目的に策定されたものである。 具体的な経緯として，本手引き策定は 2017 年に始まった Japan Pathology Artificial Intelligence Diagnostics Project（JP-AID）事業に端を発している。すなわち，日本医療研究開発機構（Japan Agency for Medical Research and Development; AMED）の研究開発事業として日本病理学会は JP-AID 事業をスタートさせた。この事業では，病理デジタル画像の収集，国立情報学研究所との AI 共同開発，そして開発された AI の地域病理ネットワークでの実証，を展開してきたが，その活動の一環として AI 開発者および利用者に必要な情報をガイドラインとしてまとめることとなった。JP-AID 事業での経過において，AI の診断精度に無視できないレベルの施設間変動が明らかになったからである。それには複数の要因が考えられるが，開発者と利用者である病理医に適切な情報を提供し，相互理解を深めることが上記の問題の軽減に役立つと我々は考えた。さらに，AI 領域での整備が遅れている法制度，倫理，社会的規範についても情報を整理して提供することがより有用と考え，それらを含めた「ガイドライン」の策定が始まった。さらに，策定過程の最終段階において，「ガイドライン」ではなく，「手引き」と題する方がより適切であると判断し，タイトルは変更された（本文第 1 章参照）。 本書策定の意図は上述のごとく，病理医が AI を使いこなす際に必要な情報と，AI を開発するのに有用な情報，とを提供することにある。これにより病理医の負担が軽減するとともにより質の高い病理診断が行われるようになることが期待される。
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