Researchers

SAKAI Kazuko

SAKAI Kazuko
Associate Professor
Faculty Department of Medicine
Researchmap https://researchmap.jp/wako02

Education and Career

Academic & Professional Experience

  • 2012 , Kindai University Faculty of Medicine 助教

Research Activities

Research Areas

  • Life sciences, Tumor diagnostics and therapeutics

Published Papers

  1. Changes in plasma cfDNA ERBB2 copy number reflect prognosis in HER2-positive gastric cancer: a correlative analysis of the KSCC-TROX A2 study.
    Yuki Shin; Akitaka Makiyama; Teppei Yamada; Tomomi Kashiwada; Masashi Hattori; Toshifumi Yamaguchi; Yoshiaki Shindo; Tetsuro Kawazoe; Sho Nambara; Yasuo Tsuda; Tomonori Nakanoko; Koji Ando; Tomoharu Yoshizumi; Kazuko Sakai; Kazuto Nishio; Eiji Oki
    International journal of clinical oncology  31  (8)  , 1597-1606, 26, May. 2026 
  2. Muscle loss and pentraxin-3 as predictors of immunotherapy outcomes in non-small cell lung cancer: a prospective study.
    Takaaki Masuda; Satoshi Watanabe; Ryo Suzuki; Kensuke Yanai; Ryo Yamazaki; Yumi Ando; Tomoya Wakabayashi; Susumu Tanaka; Kunihiro Shono; Naohiro Yanagimura; Miyuki Sato; Tomohiro Tanaka; Koichiro Nozaki; Yu Saida; Kenjiro Shima; Yosuke Kimura; Nobumasa Aoki; Yasuyoshi Ohshima; Toshiyuki Koya; Kazuko Sakai; Kazuto Nishio; Motohiko Yamazaki; Hiroyuki Ishikawa; Toshiaki Kikuchi
    Scientific reports  16  (1)  6, May. 2026 
  3. Mutation-Specific Response to Ramucirumab in EGFR-Mutated Metastatic NSCLC: Insights From Circulating Cell-Free DNA Profiling (Liquid Biopsy Japan Addendum of RELAY Phase 3 Randomized Study).
    Kazuto Nishio; Kazuko Sakai; Makoto Nishio; Takashi Seto; Carla Visseren-Grul; Michelle Carlsen; Sotaro Enatsu; Tomoko Matsui; Kazuhiko Nakagawa
    JTO clinical and research reports  7  (5)  , 100963-100963, May. 2026 

MORE

Conference Activities & Talks

  1. 非小細胞肺癌患者における血小板遺伝子発現の腫瘍環境の影響とMRDモニタリングへの応用 , 西尾 和人; 坂井 和子; 小原 秀太; 須田 健一; 津谷 康大; 光冨 徹哉 , 肺癌 , Dec. 2024
  2. 肺癌におけるRWDの活用 アファチニブからオシメルチニブへの逐次投与を評価する前向き観察研究 Gio-Tag Japan , 角 俊行; 秦 明登; 吉岡 弘鎮; 藤阪 保仁; 守田 亮; 大杉 純; 三井 匡史; 太田 登博; 森田 智視; 坂井 和子; 西尾 和人; 片上 信之 , 肺癌 , Oct. 2024
  3. EGFR変異陽性非小細胞肺癌患者に対するアファチニブ±ベバシズマブ療法のバイオマーカー探索 , 二宮 貴一朗; 坂井 和子; 大橋 圭明; 石川 暢久; 上月 稔幸; 久山 彰一; 金地 伸拓; 横山 俊秀; 二宮 崇; 堀田 勝幸; 西尾 和人; 木浦 勝行 , 肺癌 , Oct. 2024

MORE

MISC

  1. 胃癌におけるCLDN18.2中等度発現の腫瘍内不均一性に関する研究(Intratumoral Heterogeneity of Intermediate CLDN18.2 Expression in Gastric Cancer) , 川中 雄介; 稲垣 千晶; 大倉 將生; 三谷 誠一郎; 白石 直樹; 坂井 和子; 西尾 和人; 木村 豊; 千葉 康敬; 若狭 朋子; 川上 尚人; 林 秀敏 , 日本胃癌学会総会記事 , 98回 , 922 , 922 , Mar. 2026
    Summary:BACKGROUND: CLDN18.2-targeted therapies show promise in HER2-negative, CLDN18.2-positive advanced gastric cancer (GC); however, cutoffs defining CLDN18.2 positivity vary across studies. Tumors with high expression (moderate to strong membranous expression in ≥ 75% of tumor cells) generally exhibit intratumoral homogeneity and a uniform staining pattern, but intratumoral heterogeneity and staining pattern of CLDN18.2 at lower expression thresholds remains unclear. This study investigated intratumoral heterogeneity of CLDN18.2 by comparing inter-block concordance of expression levels and staining patterns in GC. METHODS: Eighty-six resected GC specimens were retrospectively analyzed using CLDN18.2 immunohistochemistry on two tissue blocks per tumor. CLDN18.2 expression was categorized as high (≥ 75%), intermediate (< 75% and ≥ 40%), or negative (< 40%), and staining patterns as uniform or variable. Inter-block concordance of expression levels and staining patterns and their influence on concordance and outcomes were assessed. RESULTS: Overall inter-block concordance of expression levels was high (77%, κ = 0.89). Discordance was substantially higher in intermediate expression tumors (63.5%) than in high (15.5%) or negative (19%) expression tumors. Uniform staining was observed exclusively in high expression tumors, whereas all intermediate expression tumors displayed variable staining (100%). Among high expression tumors, inter-block concordance was substantially higher with uniform staining (98.0%) than with variable staining (71.5%). CLDN18.2 expression and staining pattern heterogeneity were not associated with worse survival. CONCLUSION: Significant intratumoral heterogeneity of CLDN18.2 expression was observed in GC, particularly in intermediate expression tumors; however, this heterogeneity does not affect survival. These results highlight the importance of standardized assessment methods when applying lower thresholds for CLDN18.2-targeted therapies.
  2. PTPRRのダウンレギュレーションにより誘導されるEGFRの恒常的活性化はKRAS阻害薬耐性を付与する(Constitutive activation of EGFR induced by downregulation of PTPRR confers resistance to KRAS inhibitors) , 金村 宙昌; 竹原 俊幸; 前西 修; 冨田 秀太; 岩脇 菜摘; 國政 啓; 中山 智裕; 渡邊 諭美; 鈴木 慎一郎; 坂井 和子; 東 公一; 西尾 和人; 中川 和彦; 林 秀敏; 米阪 仁雄 , 肺癌 , 65 , 5 , 394 , 394 , Nov. 2025
  3. Discovery of an anticancer seed targeting cancer stem cells and analysis of its mode of action , Miyuki Matsui; Hiroaki Ikeda; Kazuko Sakai; Kazuto Nishio; Masaya Imoto; Hideaki Kakeya , MOLECULAR CANCER THERAPEUTICS , 24 , 10 , B38 , B38 , 22, Oct. 2025

MORE

Research Grants & Projects

  1. Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Evaluation of minimal residual disease in postoperative lung cancer using platelet RNA influenced by the tumor environment. , Kindai University
  2. 日本学術振興会, 科学研究費助成事業, 血中遊離核酸検査の質保証と技能試験の開発；精確な結果に基づくゲノム医療をめざして , 浜松医科大学
  3. 日本学術振興会, 科学研究費助成事業, 血中遊離核酸検査の質保証と技能試験の開発；精確な結果に基づくゲノム医療をめざして , 浜松医科大学

MORE