Abstract 1931: The first circulating tumor cell detection technique from frozen PBMCs

Abstract

Abstract Circulating tumor cells (CTCs) enter the vasculature or lymphatic system after shedding from the primary tumor. CTCs may serve as “seed” cells for tumor metastasis. The utility of CTCs in clinical application is not fully investigated, partly due to the necessity for fresh blood samples and the lack of CTC specific antibody. Of note, there is no CTC detection tool for pediatric tumors. To overcome these drawbacks, we developed a protocol for CTC capture from frozen peripheral blood mononuclear cells (PBMCs) based on the cell-surface vimentin (CSV) antibody 84-1. CSV is a unique marker compared to others such as EpCAM because it is only specific to tumor cells and has been demonstrated to be a viable target for isolation and enumeration of CTCs across tumor types. In this study, we report the first CTC isolation technology from frozen PBMCs of osteosarcoma patients using the CSV antibody 84-1. The CTCs captured using this new protocol were validated by single cell gene sequencing analysis and mesenchymal marker α-SMA staining. Moreover, spiking analysis was also performed to ensure the specificity and sensitivity of this unique CTC capture analysis. Linear regression analysis yielded a positive correlation between the number of detected sarcoma cells and the number of sarcoma cells spiked in both fresh and frozen PBMCs. In summary, our results demonstrate for the first time, a technology to specifically detect and isolate mesenchymal origin CTCs from frozen PBMCs. This technology can be easily expanded to other types of cancers including pediatric tumors because the antibody used is universal and CTC specific. Such a technology will boost the feasibility and utility of CTC-based diagnosis and therapeutic treatment monitoring in a centralized laboratory. Citation Format: Heming Li, Izhar Singh Batth, Xueqing Xia, Frank J. Hsu, Neeta Somaiah, Keila Enitt Torres, Ruoyu Wang, Shulin Li. The first circulating tumor cell detection technique from frozen PBMCs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1931. doi:10.1158/1538-7445.AM2017-1931