Establishment of a treatment method for HER2-positive breast cancer in a preclinical model using the abscopal effect and image evaluation of therapeutic efficacy

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15844
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Shiga University of Medical Science
• Principal Investigator: Aoki Ken 滋賀医科大学, 医学部, 特任助教 (90819666)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: アブスコパル効果 / 放射線治療 / 腫瘍抗原特異的CD8陽性細胞

Outline of Final Research Achievements

The abscopal effect is the shrinkage of tumors outside the irradiated area during radiation therapy. It has been reported that the therapeutic effect is related to tumor immunity. In this study, HER2-positive tumors transplanted into mice were treated with a combination of radiation therapy and two immune checkpoint inhibitors (anti-PD1 antibody and anti-CTLA4 antibody). Tumors outside the radiation field also shrank more than each treatment alone. We reported that the mechanism is likely to involve tumor antigen-specific CD8 + T cells. No useful information could be obtained from MRI imaging findings, which are indicators for early treatment prediction of abscopal effect.

Free Research Field

放射線治療

Academic Significance and Societal Importance of the Research Achievements

本研究では腫瘍抗原特異的CD8陽性T細胞がアブスコパル効果の機序に関与している可能性が高いことを報告した。アブスコパル効果は抗原特異的な免疫応答が重要であることの裏付けとなる研究の一つであると考える。HER2陽性乳癌の治療法として、今後さらに研究が進めば放射線治療と免疫チェックポイント阻害薬の組み合わせも治療方法のオプションの一つとなりうることを示唆した研究であると考える。