A new diagnostic algorithm using biopsy specimens in adult T-cell leukemia/lymphoma: combination of RNA in situ hybridization and quantitative PCR for HTLV-1

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K07438
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 49020:Human pathology-related
• Research Institution: Nagoya University (2021); University of the Ryukyus (2019-2020)
• Principal Investigator: Karube Kennosuke 名古屋大学, 医学系研究科, 教授 (20508577)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 成人T細胞白血病/リンパ腫

Outline of Final Research Achievements

Histopathological distinction between adult T-cell leukemia/lymphoma (ATLL) and other T-cell neoplasms is often challenging. Here we developed a new diagnostic algorithm for the accurate diagnosis of ATLL using FFPE samples. This method combines two HTLV-1 detection assays, namely, ultrasensitive RNA in situ hybridization using RNAscope for HTLV-1 bZIP factor (HBZ-RNAscope), and quantitative PCR targeting the tax gene (tax-qPCR). As a result, tax-qPCR had a higher ATLL identification rate than HBZ-RNAscope (88% [52/59], and 63% [39/62], respectively). However, HBZ-RNAscope clearly visualized the localization of HTLV-1-infected tumor cells and its identification rate increased to 94% (17/18) when the analysis was limited to samples up to 2 years old, indicating its usefulness in the daily diagnosis. This method is expected to replace Southern blot hybridization (SBH) and increase the accuracy of the diagnosis of ATLL.

Free Research Field

人体病理学

Academic Significance and Societal Importance of the Research Achievements

ATLLの診断のためにはHTLV-1ウイルスの存在を証明する必要があるが、これまで手技が煩雑で生検体が必要なサザンブロット法が主流であった。今回の研究によりホルマリン固定標本でもウイルスの検出が可能になったことで、ATLLの病理学的診断における迅速性、正確性が大きく高まったと言える。さらに、病変組織中で直接ウイルスを「見る」ことができることで、ATLLの病態解明にも大きく貢献したと言える。