Elucidation of anti-tumor immune response by anti-PD-1 antibody in EMAST-positive gastric cancer

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K17610
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55020:Digestive surgery-related
• Research Institution: Mie University
• Principal Investigator: Kitajima Takahito 三重大学, 医学部附属病院, 助教 (30586772)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 胃癌 / EMAST

Outline of Final Research Achievements

EMAST occurs in approximately 30% of gastric cancers, and it has been demonstrated that there is no association with chronic inflammation induced by EBV. In addition to MSI-H and EBV-positive gastric cancers, cases of EMAST-positive gastric cancer also demonstrated a high therapeutic efficacy of anti-PD-1 antibodies. Compared to MSS gastric cancer, the correlation between prognosis and 4-1BB expression differs, suggesting that a distinct immune response may contribute to EMAST-positive gastric cancer.

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Academic Significance and Societal Importance of the Research Achievements

EMAST陽性胃癌に関して治療効果ならびに治療効果予測に関して基礎的、臨床的検討を行うことで胃癌患者における抗PD-1抗体の免疫療法の新たな治療対象の可能性について検討し、EBVや4-1BBの炎症・免疫応答とは異なる関与の可能性を証明した。今後は更なる免疫応答との関連を検討するともに、抗PD-1抗体の治療効果との相関を検証することで、EMAST発現と癌組織免疫応答の機序解明を進めていく予定であり、本研究成果はその試金石となりうる役割を果たしていると考える。