Clinical Validation of a Circulating Tumor Cell Assay Using Density Centrifugation and Automated Immunofluorescence Microscopy.

Objectives: The US Food and Drug Administration (FDA)-approved CELLSEARCH assay (Menarini Silicon Biosystems) for circulating tumor cells (CTCs) relies on expression of an epithelial cell adhesion molecule to enrich for CTCs. We sought to validate a CTC assay (RareCyte) for clinical use that instead collects a buffy coat preparation enriched for CTCs.

Methods: Normal peripheral blood specimens spiked with cultured breast and prostate cancer cells and 47 clinical samples were used to validate assay performance.