Local Immune Environment and Pathological Significance in Salivary Gland Carcinoma

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K16864
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Osaka Medical and Pharmaceutical University
• Principal Investigator: HIGASHINO MASAAKI 大阪医科薬科大学, 医学部, 講師 (30397278)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 唾液腺癌 / PD-L1

Outline of Final Research Achievements

To investigate the relationship between PD-L1 expression and survival rate in parotid carcinoma, PD-L1 expression was investigated by immunohistochemical analysis in 127 patients with parotid carcinoma. PD-L1 expression was found in 28.3% of parotid carcinomas, with the expression being higher in tumors with a higher stage, a higher-grade, and node positive cases. However, the 5-year disease-specific survival rate was 82.2% for the patients with PD-L1 positive and 86.9% for those with PD-L1 negative tumors, showing no significant difference. PD-L1 expression was positive in approximately 50% of high- grade carcinomas, which was similar to the level in head and neck squamous cell carcinoma. Therefore, it could be a possible new therapeutic option for patients with highly malignant parotid tumors that have a poor prognosis.

Free Research Field

耳鼻咽喉科

Academic Significance and Societal Importance of the Research Achievements

唾液腺癌は希少癌であり、再発転移の際の標準治療は確立されていない。しかし、高悪性度の唾液腺癌は高率に遠隔転移を来たすが、これまでは頭頸部扁平上皮癌の治療に準じた治療薬を選択せざるを得なかった。このたび、頭頸部扁平上皮癌に対して、PD-L1を介した免疫チェックポイント阻害薬の有効性が確認され、再発転移頭頸部悪性腫瘍に対して、保険承認された。その承認にあたり、PD-L1が高発現していることが良い適応であることが指摘されている。本検討において、耳下腺癌でPD-L1が高悪性度癌で有意に発生率が高いことがわかり、免疫チェックポイント阻害薬の良い適応になる可能性が示唆された。