e13500 Background: The detection of circulating tumor cells (CTCs) using immunomagnetic EpCAM-based capture methods has been conceptually accepted as a “liquid tumor biopsy”. However, these methods have limited the recovery of CTCs for molecular profiling applications. We developed a novel continuous flow dielectrophoresis field-flow fractionation (DEP-FFF) device, ApoStream for antibody-independent capture of circulating cancer cells (CCCs), with improved recovery across multiple cancer types and preserved viability of CCCs for downstream characterization. Methods: The performance of ApoStream was demonstrated using a low EpCAM expressing cell line, SKOV3. ApoStream was further used to enrich CCCs from various cancer patient blood. Prostate, breast and NSCLC CCCs were stained for cytokeratin (CK), CD45, and DAPI; melanoma CCCs were stained with S100, CD45 and DAPI. CCC enumeration was performed using laser scanning cytometry. Results: In system precision performance studies, average inter-day recovery on the ApoStream was 80.3 ± 3.5%, CV = 4.3% when cancer cells were spiked into buffer, and 78.5 ± 3.0%, CV = 3.3% when cancer cells spiked into ~10 million healthy peripheral blood mononuclear cells (PBMCs). Linearity performance was demonstrated with spiking 5-2600 SKOV3 cells into 10 million PBMCs (R2=1). Cell viability was not affected by processing through ApoStream device. High CCC recovery from metastatic cancer patient blood samples was obtained with counts ranging from 0 - 2630 (NSCLC, n=66), 0 - 3490 (prostate, n=29), 10 - 968 (breast, n=11), and 3 - 3120 (melanoma, n=13) CCCs per 7.5 mL blood. Positive CCC counts were obtained in 90% of NSCLC samples, 93% of prostate cancer samples, 100% breast cancer and melanoma specimens. There were no CK+ cells detected in healthy donor blood controls. Conclusions: Improved CCC recovery from various cancer types was demonstrated with the ApoStream device. ApoStream provides an antibody-independent method for capture of viable CCCs that enables further downstream molecular characterization of rare cells for use in clinical applications. Acknowledgements: Funded by NCI Contract No. HHSN261200800001E.