Abstract A004: Full spectrum isolation technique-based dual circulating rare cells analysis to maximize early cancer diagnosis
Authors: Woo Hyeongjung , Joosse Simon A , Harten Frederike , Hilpert Felix , Pantel Klaus , Kim Minseok S. 
Published: November 2024

Abstract
Liquid biopsy (LB) is essential in precision medicine, enabling real-time tumor monitoring through repeated sampling. However, its diagnostic sensitivity and accuracy are limited by the low detection rate of circulating tumor cells (CTCs). For example, in breast cancer, the CTC detection rate exhibited only 20%, significantly limiting its clinical utility. This limitation arises since existing technologies selectively isolate specific phenotypes of CTCs, failing to capture others, such as mesenchymal CTCs, which are associated with poor prognosis. These mesenchymal CTCs often evade detection due to their lack of EpCAM expression and high deformability, making difficult to isolate them with traditional filter or EpCAM based methods. Additionally, conventional LB methods fail to provide critical insights into the tumor microenvironment (TME). To overcome these limitations, we developed a novel approach that improves LB diagnostic sensitivity and accuracy by (1) creating a technology to isolate all types of CTCs, regardless of marker expression or size, and (2) simultaneously analyzing CTCs and circulating cancer-associated fibroblasts (cCAFs). This dual approach addresses the challenges of low sensitivity and accuracy by enabling the isolation of a broader range of CTCs, including mesenchymal types, and by incorporating cCAF analysis. cCAFs, derived from the TME and found in the bloodstream, provide valuable insights into the TME that are hard to obtain through traditional methods. Analyzing cCAFs alongside CTCs offers a more comprehensive understanding of tumor biology and its microenvironment, leading to improved diagnostic accuracy, especially in early-stage cancer. In our study involving 55 breast cancer patients, we demonstrated that while CTCs were undetectable in 42.9% of early-stage patients, cCAFs were detected in all cases and were found to be 10 times more abundant than CTCs. Importantly, for the first time, this study uncovers that the diverse CAF subtypes previously identified in tissue samples also exist in the bloodstream, highlighting their critical role in providing TME-related insights. In addition, cCAF subtypes vary with hormonal receptor expression, and their marker analysis allows for 80.9% accurate classification of breast cancer subtypes. We applied this approach to early-stage breast cancer patients, for whom diagnosis through liquid biopsy is particularly difficult, and found that the combined analysis of CTCs and cCAFs achieved a 18% improvement in accuracy, with the AUC increasing from 0.6817 to 0.8009 compared to CTC analysis alone. This innovative approach significantly enhances LB by simultaneously isolating all CTC subtypes and incorporating cCAF analysis, thereby offering a more sensitive and accurate diagnostic tool. Beyond improving breast cancer diagnostics, this method has the potential to be applied to other tumor types and could also prove valuable for prognosis prediction and therapeutic response monitoring, ultimately leading to better patient outcomes and more effective cancer treatment strategies.
Citation Format: Hyeongjung Woo, Simon A Joosse, Frederike Harten, Felix Hilpert, Klaus Pantel, Minseok S. Kim. Full spectrum isolation technique-based dual circulating rare cells analysis to maximize early cancer diagnosis [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A004.