4.4. CellSearch Analyses and CTC Enumeration

Peripheral blood (7.5 mL) was collected into CellSave^® tubes and EpCAM-positive CTCs were captured and enumerated by the FDA-cleared CellSearch^TM platform (Menarini Silicon Biosystems Inc., Huntingdon Valley, PA, USA) following the manufacturer guidelines, according to the CTC definition by CellSearch (EpCAM+/CK+/DAPI+/CD45− cells). CTC enumeration of blood from NSG mice was performed using 7.0 mL of blood from healthy donors spiked with 500 µL of mouse blood using the CellSearch Circulating Epithelial Cell Kit (Menarini Silicon Biosystems, Inc.). Fluorescent CTCs were imaged and enumerated by the automated CellBrowser software (Menarini Silicon Biosystems, Inc.) according to the manufacturer guidelines.