Sakatani Toru, Sumiyoshi Takayuki, Kita Yuki, Takada Hideaki, Nakamura Kenji, Hamada Akihiro, Murakami Kaoru, Sano Takeshi, Goto Takayuki, Sawada Atsuro, Akamatsu Shusuke, Saito Ryoichi, Kobayashi Takashi
Department of Urology, Kyoto University School of Medicine, Kyoto, Japan.
Department of Urology, Kansai Medical University, Hirakata, Japan.
JCO Precis Oncol. 2025 Jan;9:e2400472. doi: 10.1200/PO-24-00472. Epub 2025 Jan 6.
Circulating tumor DNA (ctDNA) analysis is an alternative to tissue biopsy for genotyping in various cancers. We aimed to establish a plasma ctDNA sequencing assay, then evaluate its clinical utility in advanced urothelial cancer (UC).
This study included 82 patients with muscle-invasive or metastatic UC. A total of 158 blood samples and 73 tumor tissue samples were sequenced using our designed panel covering 53 UC-relevant genes and promoter. We investigated the association between the proportion of ctDNA in total cell-free DNA (ctDNA fraction) and response to pembrolizumab treatment. ctDNA dynamics were explored during systemic therapy.
In paired tissue-ctDNA samples with estimated tumor fraction, half (50.2%) of the somatic mutations were shared between both sources, while some (17.6%) mutations were found only in ctDNA. In the metastatic setting, on-treatment increase in ctDNA fraction during pembrolizumab treatment was significantly associated with a poor response rate (18.7% 76.1%; = .001) and progression-free survival (median 2.8 9.8 months; < .001). A comparison of cancer cell fraction, the fraction of tumor cells carrying somatic mutations, between pembrolizumab initiation and on-treatment showed a strong correlation among patients where ctDNA fraction increased during treatment ( = 0.73). By contrast, no correlation was observed in patients without ctDNA fraction increase ( = 0.09). Most mutations newly detected at pembrolizumab resistance have already been identified in tumor tissues at earlier stages.
Our newly established assay is suitable for assessing the genomic profile of ctDNA in patients with advanced UC. Our data may support future analyses of prognostic or predictive biomarkers for UC.
循环肿瘤DNA（ctDNA）分析是各种癌症基因分型中组织活检的一种替代方法。我们旨在建立一种血浆ctDNA测序检测方法，然后评估其在晚期尿路上皮癌（UC）中的临床应用价值。
本研究纳入了82例肌肉浸润性或转移性UC患者。使用我们设计的覆盖53个UC相关基因和启动子的检测板对总共158份血液样本和73份肿瘤组织样本进行了测序。我们研究了游离DNA中ctDNA的比例（ctDNA分数）与帕博利珠单抗治疗反应之间的关联。在全身治疗期间探索了ctDNA动态变化。
在具有估计肿瘤分数的配对组织-ctDNA样本中，两种来源之间共有一半（50.2%）的体细胞突变，而一些突变（17.6%）仅在ctDNA中发现。在转移情况下，帕博利珠单抗治疗期间ctDNA分数的治疗中增加与低反应率（18.7%对76.1%；P = 0.001）和无进展生存期（中位数2.8对9.8个月；P < 0.001）显著相关。帕博利珠单抗开始治疗和治疗期间携带体细胞突变的肿瘤细胞分数（癌细胞分数）的比较显示，治疗期间ctDNA分数增加的患者之间存在强相关性（r = 0.73）。相比之下，ctDNA分数未增加的患者中未观察到相关性（r = 0.09）。在帕博利珠单抗耐药时新检测到的大多数突变在早期肿瘤组织中已被鉴定出来。
我们新建立的检测方法适用于评估晚期UC患者ctDNA的基因组概况。我们的数据可能支持未来对UC预后或预测生物标志物的分析。
