PD02-09 ctDNA DETECTION OF NON-CORDING MUTATION IN PLEKHS1 BY DIGITAL PCR ENABLES EARLY PREDICTION OF RECURRENCE IN MUSCLE-INVASIVE BLADDER CANCER

You have accessJournal of UrologyBladder Cancer: Invasive I (PD02)1 May 2024PD02-09 ctDNA DETECTION OF NON-CORDING MUTATION IN PLEKHS1 BY DIGITAL PCR ENABLES EARLY PREDICTION OF RECURRENCE IN MUSCLE-INVASIVE BLADDER CANCER Takashi Matsumoto, Tsukahara Shigehiro, Masaki Shiota, Shunsuke Goto, Jun Mutaguchi, Keisuke Monji, Junichi Inokuchi, Keisuke Kodama, and Masatoshi Eto Takashi MatsumotoTakashi Matsumoto , Tsukahara ShigehiroTsukahara Shigehiro , Masaki ShiotaMasaki Shiota , Shunsuke GotoShunsuke Goto , Jun MutaguchiJun Mutaguchi , Keisuke MonjiKeisuke Monji , Junichi InokuchiJunichi Inokuchi , Keisuke KodamaKeisuke Kodama , and Masatoshi EtoMasatoshi Eto View All Author Informationhttps://doi.org/10.1097/01.JU.0001008836.73392.92.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Detection of mutations in circulating tumor DNA (ctDNA) in blood is expected to evaluate minimally residual disease and provide early therapeutic intervention in urothelial carcinoma. However, expensive next-generation sequencing (NGS) is not feasible. Therefore, there is a need to develop a monitoring method with high sensitivity and at a lower cost to detect multiple hotspot mutations common to patients. It was recently reported that hotspot mutations are also common in non-coding regions. We detected hotspots in non-cording regions and investigated the concordance between ctDNA in blood and follow-up over time with imaging tests in the clinical practice. METHODS: We enrolled patients diagnosed with urothelial carcinoma between May 2019 and October 2021 at single institution in Japan. Tumor and blood were collected prospectively. A panel was designed for a non-coding region of 33 kbp, and DNA sequences of cancer tissues were analyzed by NGS. Common single nucleotide polymorphisms were removed by Japanese whole genome reference panel in Tohoku medical megabank organization. We designed primers for the detected hotspot mutations and performed limit of detection of variant allele frequency (VAF) in vitro using digital PCR. Finally, ctDNA mutations were detected in blood of patients with muscle-invasive bladder cancer and matched with clinical imaging studies. This study was approved by the Institutional Review Board (#2020-254). RESULTS: 102 cases with urothelial carcinoma were enrolled. There were 35 cases of muscle-invasive bladder cancer (MIBC), 42 cases of non-muscle-invasive bladder cancer (NMIBC), and 25 cases of upper tract urinary cancer (UTUC), respectively. The median sequence data for NGS was 2.56 Gb per a case. PLEKHS1 mutations were identified in 14 (39%) patients with MIBC, and in 18 (43%) patients with NMIBC. TERT mutations were identified in 22 (63%) patients with MIBC, and in 25 (60%) patients with NMIBC. We validated to detect 0.125% VAF with originally designed primer sets for PLEKHS1 by digital PCR. 21 patients were followed with CT-scan and ctDNA in blood after cystectomy. Median follow up was 16.4 month. Among them, PLEKHS1 mutation detected in 7 (33.3 %) patients and TERT mutation detected in 9 (42.9 %) patients. 11 patients with MIBC had clinical recurrence accompanied with elevated VAF of ctDNA. With a threshold of 0.5%, PLEKHS1 mutation in ctDNA predicted recurrence or metastasis 102.5 days earlier than imaging, which exceeded detection by TERT mutation (vs 64.5 days). Eventually, multiple detection of PLEKHS1 and TERT predicted recurrence 126.5 days IQR: 29.0-185.3 earlier than imaging. CONCLUSIONS: NGS of non-coding regions revealed that patients with MIBC and NMIBC harbor hotspot mutations in PLEKHS1. PLEKHS1 mutation is promising biomarker to predict earlier recurrence than CT-scan. Multiple detection of PLEKHS1 and TERT mutations by digital PCR contributes to reliable recurrence prediction. Source of Funding: Research funding from Denka corporation © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e73 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Takashi Matsumoto More articles by this author Tsukahara Shigehiro More articles by this author Masaki Shiota More articles by this author Shunsuke Goto More articles by this author Jun Mutaguchi More articles by this author Keisuke Monji More articles by this author Junichi Inokuchi More articles by this author Keisuke Kodama More articles by this author Masatoshi Eto More articles by this author Expand All Advertisement PDF downloadLoading ...