Blood-based molecular profiling of Chinese patients with advanced renal cell carcinoma

e16550 Background: The therapeutic landscape of renal cell carcinoma (RCC) has rapidly expanded, and there is an urgent need to develop noninvasive biomarkers that can select an optimal therapy in real time. Next-generation sequencing (NGS)-based profiling of circulating tumor DNA (ctDNA) shows promise for noninvasive detection. To evaluate the clinical utility of ctDNA analysis in RCC, we aimed to analyze the molecular characteristics of RCC using ctDNA by NGS. Methods: A total of 189 plasma samples and 26 matched tumor tissues from Chinese patients with advanced renal cell carcinoma (n = 189) were analyzed by Acornmed panel with 808 cancer-related genes, and matched white blood cell as germline comparators. Results: Overall, 29 germline mutations were detected in 14.3% (27/189) patients, such as TSC2 (5/189, 2.65%), FH (3/189, 1.6%) and VHL (2/189, 1.1%), of which 10 germline aberrations in DNA damage repair (DDR) genes were detected in 5.3% patients (10/18). In addition, a total of 1590 somatic variations were identified in 96.8% (183/189) ctDNA, including 1278 nonsynonymous single nucleotide variants, 126 small insertions or deletions, 75 copy number variations. And the median blood tumor mutation burden (bTMB) was 4.36 mut/Mb. Mutations in VHL (36/189, 19.4%) were the most prominent variation, followed by those in TP53 (19/189, 10.0%), BAP1 (12/189, 6.3%), PBRM1 (10/189, 5.3%) and SETD2 (7/189, 3.7%). Moreover, totals of 154 clinically actionable mutations from 92 patients (48.7%) were identified. In 26 patients with both tumor tissues and plasma samples, sequencing detected alterations in 100% (26/26) tumor tissue DNA (tDNA) and 96.2% (25/26) ctDNA, respectively. Furthermore, 29.6% of mutations of tissues were founded in ctDNA, and 21.6% of mutations of ctDNA were detected in tissues. Among them, 73.1% (19/26) patients had at least one overlapping variant called by tDNA and ctDNA. The most common shared mutation was VHL (5/26, 19.2%). Meanwhile, four shared copy number variants were detected in two patients (15.4%). Conclusions: Our study contributes to understand the molecular characteristics of RCC using ctDNA, which is a viable option for tissue when tissue is difficult to obtain. Furthermore, ctDNA testing by NGS is helpful for drug selection and provides more effective treatment options for RCC, particularly for hereditary RCC.