Detection of ctDNA in patients with esophageal squamous cell carcinoma using NGS and digital PCR

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K10586
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Digestive surgery
• Research Institution: Osaka University
• Principal Investigator: Kurokawa Yukinori 大阪大学, 医学系研究科, 講師 (10470197)
• Co-Investigator(Kenkyū-buntansha): 山崎 誠 大阪大学, 医学系研究科, 准教授 (50444518)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 食道外科学 / ctDNA / 次世代シーケンサー / 分子バーコード / liquid biopsy

Outline of Final Research Achievements

Next-generation sequencing (NGS) with molecular barcodes (MB) is a novel method that enables the highly sensitive detection of circulating tumor DNA (ctDNA) in a relatively wide range of genes. We examined the utility of NGS with MB for detecting ctDNA in patients with esophageal squamous cell carcinoma (ESCC) at each time point during the treatment course. The maximum frequency of background errors were 3.22% using NGS without MB and 0.08% with MB, which indicated that the sensitivity of ctDNA detection using NGS with MB was much higher than without MB. In 1 patient who had recurrence half a year after surgery, only NGS with MB could detect ctDNA even at 4 weeks after surgery, at a frequency of 0.20%. Overall, NGS with MB enabled comprehensive and highly sensitive detection of ctDNA in a patient with ESCC. This novel method may be useful for the clinical diagnosis of ESCC.

Free Research Field

消化器外科学

Academic Significance and Societal Importance of the Research Achievements

BEAMingやデジタルPCRなどといったctDNAの検出に広く行われてきた手法は、特定部位の変異の高感度な検出には優れているが、食道癌などのように様々な部位に変異を生じる疾患では汎用性に乏しい。一方、NGSを用いた方法では少数のプライマーセットで網羅的な遺伝子解析が可能であるが、検出感度が低く、いずれも臨床応用には問題点が挙げられる。本研究では、分子バーコードを用いたNGSを用いることで食道癌ctDNAの高感度かつ網羅的な解析に成功した。本手法はctDNAを用いた臨床診断に有用である可能性が示唆された。