Abstract A199: Using Fiber Array Scanning Technology (FAST) Platform for sensitive detection and analysis of circulating tumor cells with a hybrid epithelial/mesenchymal phenotype from non-small cell lung cancer.

Circulating tumor cell (CTC) analysis uses a “liquid biopsy” to provide critical information regarding diagnosis, prognosis, response to therapy and risk of relapse. To date, CTC analysis in non-small cell lung cancer (NSCLC) patients using epithelial cell adhesion molecule (EpCAM) immunomagnetic enrichment techniques has met with limited success. This is thought to be because the majority of CTCs detected in NSCLC patients demonstrate the mesenchymal phenotype to various extents, and epithelial markers on CTCs are lost during the epithelial-mesenchymal transition (EMT). We report here that the non-enrichment, FAST platform can be used for rapid detection and characterization of CTCs with a hybrid EMT phenotype. We developed a model using whole blood from healthy donors spiked with human NSCLC cell lines that have been classified as having varying levels of EMT. These included “more epithelial, high EpCAM type” (A549 and EKVX), and “more mesenchymal, low EpCAM type” (H2228 and Calu-1) cell lines. A multiplexed assay was developed to simultaneously evaluate cellular and molecular markers of the hybrid phenotypes. FAST was used to develop an optimized assay with high yields (more than 75% retention, detection performance as high as 1 CTC/5 ml blood) of CTCs with hybrid phenotype. 100% of NSCLC cells detected by the FAST platform co-expressed mesenchymal/stem cell markers such as Vimentin, N-Cadherin and ALDH1. FACS analysis of NSCLC cells confirmed levels of EpCAM expression ranging from negative to high. CTCs harboring anaplastic lymphoma kinase (ALK) translocations also demonstrated mesenchymal-like phenotypes. Finally, a high incidence of CTC clusters (circulating tumor microemboli; CTM) that have been previously reported with the hybrid phenotype, was detected from Stage IV NSCLC patients. These data illustrate that the FAST platform is suitable for high-sensitivity detection and comprehensive analyses of the full spectrum of EMT phenotypes in NSCLC CTCs. We have also developed assays to multiplex cellular and molecular biomarkers on single CTCs to guide personalized therapy, including the detection of ALK to select patients appropriate for Crizotinib therapy. Further work is planned to analyze the dynamic change of EMT components in CTCs during disease progression to correlate EMT biomarkers in CTCs with patient outcomes and provide new diagnostic tools for lung cancer. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A199. Citation Format: Xiaohe Liu, Janey C. Ly, Laurie Kara, Heather Wakelee, Nathan Collins, Keith Laderoute, Lidia C. Sambucetti. Using Fiber Array Scanning Technology (FAST) Platform for sensitive detection and analysis of circulating tumor cells with a hybrid epithelial/mesenchymal phenotype from non-small cell lung cancer. [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 A199.