Evaluating method for tumor immune microenvironment by using the functional imaging

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K16902
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Otorhinolaryngology
• Research Institution: Gifu University
• Principal Investigator: Ohashi Toshimitsu 岐阜大学, 医学部附属病院, 併任講師 (80707860)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 頭頸部癌 / FDG-PET/CT / Warburg効果 / M2マクロファージ

Outline of Final Research Achievements

Fluorine-18 fluorodeoxyglucose uptake detected by positron emission tomography/computed tomography (FDG-PET/CT) is considered as a good indicator of aerobic glycolysis. In this study, whole-body FDG-PET/CT parameters; the maximum standardized uptake value (SUVmax) and mean SUV (SUVmean), were correlated with the C-reactive protein level, and neutrophil count. Furthermore, we investigated the relationships between FDG-PET/CT parameters and M2-macrophage polarization in head and neck squamous cell carcinoma (HNSCC) tissue. FDG-PET/CT has the potential to reflect cancer-related chronic inflammation and immunosuppressive conditions in cancer patients. FDG-PET/CT parameters appear to be useful in assessing the immune status in HNSCC.
Doppler ultrasound was used to measure blood flow in metastatic lymph nodes. Metastatic lymph nodes with decreased blood flow are related with decreased macrophage infiltration. This result was contrary to my hypothesis.

Free Research Field

腫瘍免疫

Academic Significance and Societal Importance of the Research Achievements

解糖系が亢進（SUVmax、SUVmean が高値）している、つまりWarburg効果が亢進しているがんは、炎症が誘導され免疫抑制状態になっていると考えられた。炎症が誘導され免疫抑制状態になっているがんでは、治療抵抗性が高いと予想される。特に免疫チェックポイント阻害薬の治療効果に大きく関わるかもしれない。今回の結果は、FDG-PET/CTが、がん微小環境の免疫状態を反映することを示しており、将来的に免疫チェックポイント阻害薬などの治療効果を予測ツールとして使用が期待される。