J.W. Kamande, M.L. Hupert, M.A. Witek, H. Wang, R.J. Torphy, U. Dharmasiri, S.K. Njoroge, J.M. Jackson, R. D. Aufforth, A. Snavely, J.J. Yeh, S.A. Soper, “Modular microsystem for the isolation, enumeration, and phenotyping of circulating tumor cells in patients with pancreatic cancer,” Analytical Chemistry, vol. 85, pp. 9092 – 9100, 2013.
In this manuscript, we discuss the development and clinical use of a thermoplastic modular microsystem for the high-throughput analysis of CTCs directly from whole blood. The modular system offers some innovative features that address challenges currently associated with many CTC platforms; it can exhaustively process 7.5 mL of blood in less than 45 min with recoveries >90%. In addition, the system automates the postselection CTC processing steps and thus, significantly reduces assay turnaround time (from selection to enumeration <1.5 h as compared to >8 h for many reported CTC platforms). The system is composed of 3 functional modules including (i) a thermoplastic CTC selection module composed of high aspect ratio (30 μm × 150 μm) channels containing anti-EpCAM antibodies that is scalable in terms of throughput by employing channel numbers ranging from 50 to 320; the channel number is user selected to accommodate the volume of blood that must be processed; (ii) an impedance sensor module for label-less CTC counting; and (iii) a staining and imaging module for the placement of released cells into a 2D array within a common imaging plane for phenotypic identification. To demonstrate the utility of this system, blood samples from patients with local resectable and metastatic pancreatic ductal adenocarcinoma (PDAC) were analyzed. We demonstrate the ability to select EpCAM positive CTCs from PDAC patients in high purity (>86%) and with excellent yields (mean = 53 CTCs per mL for metastatic PDAC patients) using our modular system. In addition, we demonstrate the ability to detect CTCs in PDAC patients with local resectable disease (mean = 11 CTCs per mL).