Abstract Introduction: Urine represents a promising, truly noninvasive biofluid for kidney cancer detection and disease monitoring. However, clinical adoption of urine cfRNA has been limited by low RNA abundance and the small sample volumes processed in standard extraction workflows. We evaluated a high-volume urine cfRNA extraction method (up to 50 mL) designed to improve analytical sensitivity for renal tumor–associated transcripts. Methods: Fresh and preserved urine was spiked with quantitative (ARM-200) and fragmented (ARM-300) RNA standards, as well as gene-specific synthetic transcripts from Anchor Molecular. The nRichDX Revolution cfRNA Max50 Kit was compared with commonly used low volume cfRNA kits. Analytical performance metrics included total cfRNA recovery, linearity across input volumes, reproducibility, and RT-qPCR detection of clinically relevant renal biomarkers (VHL, CA9, VEGFA, EPAS1/HIF2A, PAX8, HAVCR1/KIM-1, AQP1, GPX3, CXCL10). Results: Processing 30–50 mL of urine consistently increased cfRNA yield relative to 2–10 mL workflows and generated superior ΔCt values for multiple renal cancer markers. Both ARM-200 and ARM-300 standards demonstrated linear and reproducible recovery across dilution tiers, with efficient capture of short, fragmented cfRNA species relevant to renal carcinoma biology. No extraction saturation occurred at higher volumes, supporting scalability for clinical urine-based assays. Conclusions: High-volume urine cfRNA extraction markedly improves the analytical sensitivity of renal biomarker detection and overcomes a major barrier limiting the clinical utility of urine-based liquid biopsy for kidney cancer. This workflow enables more reliable detection of low-abundance, fragmented cfRNA species and may enhance early diagnosis, treatment monitoring, and longitudinal disease surveillance in patients with renal malignancies. AI Disclosure: Portions of this abstract were edited with assistance from an AI language model. Citation Format: Nafiseh Jafari, Jason Saenz, Carlos Hernandez, Daniel Cedeno, Cameron Van Dieren, Mayer Saidian, Yabin Lu. Urine liquid biopsy for kidney cancer: High-volume cfRNA extraction enhances detection of renal cancer biomarkers for early detection abstract. In: Proceedings of the AACR Special Conference in Cancer Research: Innovations in Kidney Cancer Research: From Molecular Insights to Therapeutic Breakthroughs; 2026 Mar 13-16; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86 (5Suppl₂): Abstract nr B039.
Jafari et al. (2026) studied this question.