Abstract C29: Characterization and identification of specific EGFR mutations in circulating tumor cells (CTCs) isolated from non-small cell lung cancer patients using an antibody independent method, ApoStream™: An update report.

Abstract

Abstract Background: A variety of methods for capture of rare CTCs of epithelial origin are available; most employ antibodies to epithelial cell adhesion molecule (EpCAM) and cytokeratin (CK). Using a classic phenotypic definition, a CTC is nucleated, CK(+), CD45(-) cell. However, some CTCs may elude capture as they originate from primary tumor cells which have undergone epithelial-mesenchymal transition (EMT). We report here the use of ApoStream™, a novel dielectrophoresis field-flow-assisted, antibody-free method to isolate CTCs from blood. Methods: Blood was collected from consented NSCLC patients and processed using ApoStream™. For CTC enumeration comparison, the CellSearch® FDA-approved kit was used. Isolated cells were evaluated with a multiplexed immunofluorescent assay and laser scanning cytometry was applied to identify multiple combinations of positive and/or negative staining for CK/CD45/DAPI and EpCAM. To determine specific EGFR mutations from captured CTCs, samples were analyzed using Improved and Complete Enrichment with CO-amplification at Lower Denaturation temperature (ICE COLD-PCR). Results: Blood samples from 37 NSCLC patients and 8 healthy volunteers were processed and the results of the cell populations isolated using ApoStream™ are summarized in table. EGFR mutations [exon 19 deletion and exon 21 L858R] were determined and found to be concordant when compared to tumor tissue analysis by Sanger sequencing. Conclusions: The ApoStream™ platform enriched EpCAM(+) and EpCAM(-) CTCs from the blood of NSCLC patients demonstrating utility in recovering cancer cells with multiple phenotypes. From recovered CTCs, detection of EGFR mutations was possible indicating the clinical relevance and potential utility of CTCs as an alternative to tissue biopsy. Additional sensitivity and complete mutation analysis will be presented. (a portion of this data was presented at 2013 ASCO Annual Meeting, Chicago, IL, USA) Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C29. Citation Format: Hai T. Tran, Vladislava Melnikova, Anne S. Tsao, Frank V. Fossella, Faye M. Johnson, Vali Papadimitrakoupoulou, Katherine Richardson, Marcia E. Lewis, Ben Legendre, Kenna L. Anderes, Darren W. Davis, John V. Heymach. Characterization and identification of specific EGFR mutations in circulating tumor cells (CTCs) isolated from non-small cell lung cancer patients using an antibody independent method, ApoStream™: An update report. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C29.