Prophylactic neck dissection for oral cancer based on liquid biopsy

• Project/Area Number: 20K09710
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Osaka University
• Principal Investigator: Suzuki Motoyuki 大阪大学, 大学院医学系研究科, 助教 (50632329)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2022: ¥130,000 (Direct Cost: ¥100,000、Indirect Cost: ¥30,000); Fiscal Year 2021: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2020: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: 舌癌 / リキッドバイオプシー / 口腔癌 / リンパ節転移 / 口腔がん / liquid biopsy

Outline of Research at the Start

本研究では、原発巣切除+経過観察で加療する患者を対象として、リキッドバイオプシーによりcirculating tumor DNA (ctDNA)を解析し、原発巣切除後に潜在的リンパ節転移が顕在化するよりも先行してctDNAが検出されることを後方視的且つ前方視的に実証する。本研究によりリキッドバイオプシーの有用性が確立され れば、一期的に原発巣切除のみを行い、術後にctDNAが検出される場合に限り二期的に予防的頸部郭清を行うという、個別化医療の実現に向けた礎が構築される。

Outline of Final Research Achievements

DNA targeting sequencing was performed on 27 cases of tongue cancer in which DNA was extracted and fragmented from primary tumors and blood. 23 (85%) of the cases had target gene mutations. A significant correlation between Stage and ctDNA copy number was observed (p<0.001). A strong correlation was also observed between DOI of the primary tumor and ctDNA. There were three cases in which the mutation remained in the plasma around 1 week postoperatively, and two of them subsequently recurred. Furthermore, ctDNA at the time of recurrence was detected in all but one case.

Academic Significance and Societal Importance of the Research Achievements

舌癌患者のリキッドバイオプシーによりターゲットとなる遺伝子変異は進行癌では検出可能であり、早期癌でも再発時には多くの症例で検出された。また、一部の症例では術後早期に潜在的再発を予測できた。今後有用なバイオマーカーとなり得ることが示唆された。