Assays and screens

A magnetic field cytometry-based method of detecting CTCs could help diagnose breast, prostate and other cancers. The method involved tagging tumor cell surface markers such as epithelial cell adhesion molecule (EpCAM) in patient blood samples with magnetic nanoparticle-bound antibodies; subjecting the blood to magnetic field gradients on microfluidic chips to capture the tagged, nanoparticle-bound cells; then immunostaining the captured cells to quantify levels of the antibody tags. In human blood spiked with a human prostate cancer cell line or human breast cancer cell lines, the method detected cancer cells with higher efficiency than the CellSearch Circulating Tumor Cell Kit (90-97% and less than 60%, respectively). In blood samples from a xenograft mouse model of breast cancer, the method detected decreases in EpCAM levels on CTCs between day 42 and day 53 of tumor growth. In blood samples from patients with metastatic castration-resistant prostate cancer (CRPC) or localized prostate cancer, the method detected low cell surface levels of EpCAM that correlated with high tumor histopathology scores. Next steps include designing integrated instrumentation to automate the method...