Abstract 5124: Isolation of viable circulating tumor cells from peripheral and central venous blood using a rapid microfluidic biochip
Authors: Zhou Jian , Luan Qiyue , Macaraniag Celine , Guzman Arielle , Mantice Maria , Danciu Oana , Hoskins Kent , Papautsky Ian 
Published: June 2022

Abstract
Background: Thousands of circulating tumor cells (CTCs) may be released into the blood stream of a cancer patient each day. However, only viable CTCs can cause metastasis. These viable CTCs hold the promise of deciphering the tumor heterogeneity, uncovering the mechanism of resistances to therapies, and enabling personalized treatments. Despite the continuously mounting interest, isolation of these cells remains challenging due to the multitude of factors, including rarity of the CTCs in blood, their constant exposure to therapeutic agents, and the harsh environment in the circulation. To address this, we have developed a novel microfluidic biochip capable of CTC isolation from unprocessed whole blood. Herein, we compare isolation of CTCs from the central and peripheral blood samples of metastatic breast cancer (MBC) patients using our biochip to assess impact of blood collection location on CTC count and viability.
Methods: We included 19 patients with MBC, of which 26% are white, 63% are African American, and 11% are Latino. The median age of the cohort is 58 (34-75y). All patients are undergoing therapy. A total of 36 samples (7.5 mL each) were collected from either an antecubital vein (peripheral vein) or the subcutaneous port catheter (central vein) at different time points. All samples were processed within 5 hours of blood drawn in our novel microfluidic biochip (only 40 minutes per sample, without pretreatment), followed by in situ immunostaining. CK+/EpCAM+, DAPI+ and CD45- cells were counted as CTCs. In situ live/dead assay using Calcein AM and propidium iodide was performed for some samples right after CTC isolation.
Results: CTCs were detected in all the samples (36/36), with a median of 15 CTCs per sample. A &gt;5 CTCs count was found in 86% of the samples (31/36). No correlation was found between CTC count and race/ethnicity. The CTC count in central venous samples was in the range of 6-105 (median 27), while the range was 1-45 (median 10) in the peripheral samples. The difference was found to be statistically significant (p&lt;0.001 using ANOVA). While no correlation between CTC count and patient age was found for the overall samples, we noted a significantly higher CTC count in central venous blood of younger patients (&lt;60y) than of senior patients (p&lt;0.05). Live/dead assay immediately following the microfluidic isolation found live CTCs in patient samples.
Conclusions: Viable CTCs were rapidly isolated and detected in MBC samples using our novel microfluidic biochip. Our results show that CTC count in blood drawn from central vein yields significantly higher numbers than from the peripheral vein, suggesting that central venous samples might be preferred for prognosis and monitoring to drug response in MBC patients. Viable CTCs may provide an opportunity to evaluate the mechanism of resistance to therapies. More studies with larger cohorts are needed to further confirm these findings.
Citation Format: Jian Zhou, Qiyue Luan, Celine Macaraniag, Arielle Guzman, Maria Mantice, Oana Danciu, Kent Hoskins, Ian Papautsky. Isolation of viable circulating tumor cells from peripheral and central venous blood using a rapid microfluidic biochip [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5124.