Abstract 5605: Ambient storage and stabilization of proteins and cell-free nucleic acids in whole blood samples

Abstract

Abstract Introduction: Highly anticipated advancements in biotechnology and instrumentation now allows for simultaneous detection of multiple biomarkers. This is accelerating the cancer research field towards the development of multianalyte-based in vitro diagnostic tests for early detection and/or monitoring of cancer. These multianalyte liquid biopsy tests are often based on detection of cancer-related proteins and/or tumor-specific genomic and transcriptomic changes (circulating cell-free nucleic acids) in plasma. A specialized and proprietary stabilization reagent has been developed for use in a blood collection tube with the capability to simultaneously stabilize protein biomarkers of interest and cell-free nucleic acids. Methods: Blood samples from self-proclaimed healthy donors were drawn into evacuated blood collection tubes containing a new stabilization reagent and stored at room temperature. Plasma was isolated using a general double-spin protocol (1800 × g for 15 min and 2800 × g for 15 min) and frozen at -80 °C until use. Plasma levels of proteins of interest including cancer markers and immuno-oncology checkpoint markers were measured by Ella Simple Plex Assays (Bio-Techne) and Luminex xMAP® Technology Assays (Bio-Techne, samples tested by LuminexPLORE Lab). Total cell-free nucleic acids were isolated using the QIAamp Circulating Nucleic Acid Kit and the resultant cfDNA or cfRNA was analyzed with fluorometric-based assay (quantitative) and Bioanalyzer/Tapestation (qualitative). Results: Compared with blood samples collected in EDTA and ACD-A tubes, the new stabilization reagent maintained the draw time levels of plasma proteins of interest such as TGF-β1, MMP-9, IL-8/CXCL8, CCL5/RANTES, Granzyme B, CEA and PD-L1 for up to 5 days of room temperature storage in whole blood. The reagent also effectively maintained draw time levels of plasma cell-free nucleic acids to near draw time levels. In addition, the new reagent also minimized in vitro hemolysis during room temperature storage. Conclusion: This new and breakthrough stabilization reagent simultaneously maintains the draw time levels of proteins of interest and cell-free nucleic acids for an extended period of time in whole blood. It provides cancer researchers and clinical assay developers confidence in blood sample integrity and flexibility in sample storage, transport, and processing at ambient temperature for multianalyte analysis or multiomics profiling. Citation Format: Jing Li, Lisa Bartron, Jordan LaRue, Sama Mehta, Nicholas M. George. Ambient storage and stabilization of proteins and cell-free nucleic acids in whole blood samples. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5605.