Clinical significance of the mutational landscape and fragmentation of circulating tumor DNA in renal cell carcinoma
Clinical significance of the mutational landscape and fragmentation of circulating tumor DNA in renal cell carcinoma
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DOI：
10.1111/cas.13906
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发表时间：
2019-02-01
期刊：
影响因子：
5.7
通讯作者：
Nonomura, Norio
中科院分区：
文献类型：
--
作者：
Yamamoto, Yoshiyuki;Uemura, Motohide;Nonomura, Norio
肾细胞癌(RCC)的可靠生物标志物尚未确定。循环肿瘤DNA(CtDNA)是检测和监测各种肿瘤分子特征的新兴资源。本研究旨在阐明ctDNA在肾癌中的临床应用价值。纳入53例经组织学诊断为透明细胞肾癌的患者。用血浆无细胞DNA(CfDNA)和肿瘤DNA进行靶向测序。我们应用滴状数字聚合酶链式反应(DdPCR)来验证检测到的突变。还使用基于微流控的平台和测序来评估cfDNA片段大小。CfDNA片段比例定义为小片段(50-166bp)与大片段(167-250bp)的比例。分析ctDNA突变等位基因频率与临床病程的关系。预后潜能的评估采用对数等级检验。在16例(30%)患者的cfDNA中发现38个突变，包括tp53(n=6)和vhl(n=5)，ctDNA突变等位基因频率中位数为10%。我们设计了针对11个突变的特异性ddPCR探针，并在cfDNA和肿瘤DNA中检测到相同的突变。CtDNA阳性与cfDNA片段比例显著相关(P=0.033)，提示ctDNA阳性肾癌患者cfDNA片段大小较短。有趣的是，ctDNA突变等位基因频率的变化与临床病程同时相关。CtDNA阳性和cfDNA片段化与肿瘤特异性生存不良显著相关(P<；.001，P=.011)。总之，我们的研究表明，ctDNA状态和cfDNA片段大小作为肾癌预后和疾病监测的生物标志物具有临床应用价值。
Reliable biomarkers for renal cell carcinoma (RCC) have yet to be determined. Circulating tumor DNA (ctDNA) is an emerging resource to detect and monitor molecular characteristics of various tumors. The present study aims to clarify the clinical utility of ctDNA for RCC. Fifty-three patients histologically diagnosed with clear cell RCC were enrolled. Targeted sequencing was carried out using plasma cell-free DNA (cfDNA) and tumor DNA. We applied droplet digital PCR (ddPCR) to validate detected mutations. cfDNA fragment size was also evaluated using a microfluidics-based platform and sequencing. Proportion of cfDNA fragments was defined as the ratio of small (50-166 bp) to large (167-250 bp) cfDNA fragments. Association of mutant allele frequency of ctDNA with clinical course was analyzed. Prognostic potential was evaluated using log-rank test. A total of 38 mutations across 16 (30%) patients were identified from cfDNA, including mutations in TP53 (n = 6) and VHL (n = 5), and median mutant allele frequency of ctDNA was 10%. We designed specific ddPCR probes for 11 mutations and detected the same mutations in both cfDNA and tumor DNA. Positive ctDNA was significantly associated with a higher proportion of cfDNA fragments (P = .033), indicating RCC patients with ctDNA had shorter fragment sizes of cfDNA. Interestingly, the changes of mutant allele frequency in ctDNA concurrently correlated with clinical course. Positive ctDNA and fragmentation of cfDNA were significantly associated with poor cancer-specific survival (P < .001, P = .011). In conclusion, our study shows the clinical utility of ctDNA status and cfDNA fragment size as biomarkers for prognosis and disease monitoring in RCC.