Abstract 2302: Innovative blood-based cell-free RNA whole transcriptome sequencing for comprehensive RNA profiling in patient plasma samples and its clinical applications

Abstract Background: Plasma cell-free RNA (cfRNA) holds promise for non-invasive cancer biomarker discovery, particularly in diseases like prostate cancer where specific biomarkers (AR splicing variants and TMPRSS2: ERG fusion) are detectable at the RNA level. Despite its potential, the technical challenges posed by blood cell-originated cfRNA abundance necessitates the development of robust and reliable assays for non-invasive cancer diagnostics. This study establishes and demonstrates the clinical utility of an innovative protocol for isolating and identifying tumor-originated cfRNA in plasma samples. Methods: A novel methodology was developed for the simultaneous extraction of cfDNA and cfRNA from a single blood sample tube, enabling whole transcriptome sequencing (WTS) analysis with minimal input as low as 1ng. A proprietary method was developed to selectively deplete blood cell-originated transcripts in the library. An enrichment-based WTS assay was conducted, and a customized RNASeq analysis pipeline was employed to enable expression profiling and cancer biomarker testing from the cfRNA samples. Results: The developed extraction method yielded substantial amounts of cfDNA and cfRNA from a 4 mL blood sample. Efficient depletion of blood cell-originated transcripts, achieving over 99% removal, enhanced the detection of a broader range of gene expressions in plasma. Implementation of the cfRNA WTS assay across healthy donor and cancer samples demonstrated consistency with documented biomarker status. The assay revealed significant differential clustering between cancer samples and healthy donors, with characteristic cancer genes contributing to the distinction. Reproducibility and analytical sensitivity of the developed cfRNA WTS assay were successfully validated. Conclusions: This study introduces Predicine's proprietary cfRNA WTS assay, enabling concurrent expression profiling and RNA biomarker detection in plasma samples. Overcoming technical challenges associated with blood cell-originated cfRNA, this assay represents a significant advancement in liquid biopsy-based cancer diagnostics. Citation Format: Fang Liu, Yong Huang, Min Wang, Xiangying Sun, Binggang Xiang, Shidong Jia, Pan Du, Shujun Luo. Innovative blood-based cell-free RNA whole transcriptome sequencing for comprehensive RNA profiling in patient plasma samples and its clinical applications abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 2302.