Abstract 1449: ApoStream™, a new dielectrophoretic device for antibody-independent isolation and recovery of circulating tumor cells from blood of patients with metastatic pancreatic adenocarcinoma.

Abstract

Abstract Pancreatic adenocarcinoma (PAC) remains the fourth most common cause of cancer-related mortality with a 5-year survival rate of less than 5%. The available diagnostic tools and biomarkers for PAC fail at early detection and suffer from low specificity and sensitivity. Advances in the isolation, recovery, and characterization of circulating tumor cells (CTCs) offer hope for the development of noninvasive techniques for disease detection, monitoring, and biomarker discovery. While CTC enumeration provides prognostic information in patients with various cancer types, the biological characterization of CTCs may offer insight into the molecular determinants of disease progression. Epithelial cell adhesion molecule (EpCAM) and cytokeratin (CK) dependent CTC technologies fare poorly in the metastatic PAC setting, due to altered phenotypes acquired during epithelial mesenchymal transition (EMT). The links between EMT, plectin-1, mesothelin and metastatic progression of PAC are emerging and underscore the need for biomarker information in real time. Here we used ApoStream™, a novel, antibody-independent device which uses dielectrophoretic (DEP) technology in a continuous flow system to isolate CTCs from the blood of patients with metastatic PAC and expand their phenotypic characterization in order to elucidate the population heterogeneity and characterize pancreatic specific markers (CA19-9, KRAS, plectin-1 and mesothelin). This prospective study will evaluate thirty patients. Paired blood samples from 11 metastatic PAC patients were analyzed by CellSearch® and ApoStream™. Collected cells were immunostained using antibodies against CK, CD45, DAPI, CA19-9, plectin-1 and mesothelin. CTC enumeration was performed using laser scanning cytometry (LSC). A multiplexed immunofluorescent assay and LSC analysis were applied to identify cell phenotypes based on combinations of CK, CD45, plectin-1 and mesothelin marker expression. Results:The detection of CK+/CD45−/DAPI+ cells was comparable between CellSearch® and ApoStream™ with counts ranging from 1-10 CTCs/7.5 mL blood in 50% of patients. In addition, ApoStream™, recovered CK−/CD45−/DAPI+ cells in 100% of patients with counts in the range of 12-166 cells/7.5 mL of blood. CA19-9+ cells were identified in both CK+/CD45−/DAPI+ and CK−/CD45−/DAPI+ subpopulations isolated by ApoStream™. KRAS, plectin-1 and mesothelin analysis is pending. Conclusions: ApoStream™ recovers putative CTCs with multiple phenotypes in patients with metastatic PAC. Preliminary data is encouraging and if confirmed in a larger sample size of PAC patients, ApoStream™ could prove to be a sensitive method for isolating and detecting biomarkers in CTCs of PAC patients. Acknowledgments: Supported in part by the Lockton Fund. Citation Format: Gauri Varadhachary, James Abbruzzese, Rachna Shroff, Vladislava Melnikova, Vishal Gupta, Chris Neal, Miguel Garza, David K. Hasegawa, Kenna L. Anderes, Darren Davis, Robert A. Wolff. ApoStream™, a new dielectrophoretic device for antibody-independent isolation and recovery of circulating tumor cells from blood of patients with metastatic pancreatic adenocarcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1449. doi:10.1158/1538-7445.AM2013-1449