title: Detection of EpCAM-Negative and Cytokeratin-Negative Circulating Tumor Cells in Peripheral Blood.
abstract: Enrichment of rare circulating tumor cells (CTCs) in blood is typically achieved using antibodies to epithelial cell adhesion molecule (EpCAM), with detection using cytokeratin (CK) antibodies. However, EpCAM and CK are not expressed in some tumors and can be downregulated during epithelial-to-mesenchymal transition. A micro-fluidic system, not limited to EpCAM or CK, was developed to use multiple antibodies for capture followed by detection using CEE-Enhanced (CE), a novel in situ staining method that fluorescently labels the capture antibodies bound to CTCs. Higher recovery of CTCs was demonstrated using antibody mixtures compared to anti-EpCAM. In addition, CK-positive breast cancer cells were found in 15 of 24 samples (63%; range 1-60 CTCs), while all samples contained additional CE-positive cells (range 1-41; median = 11; P = .02). Thus, antibody mixtures against a range of cell surface antigens enables capture of more CTCs than anti-EpCAM alone and CE staining enables the detection of CK-negative CTCs.
authors.affiliation: Research and Development, Biocept Inc., 5810 Nancy Ridge Drive, Suite 150, San Diego, CA 92121, USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Mikolajczyk
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Millar
authors.forename: Pavel
authors.initials: P
authors.lastname: Tsinberg
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Coutts
authors.forename: Maryam
authors.initials: M
authors.lastname: Zomorrodi
authors.forename: Tam
authors.initials: T
authors.lastname: Pham
authors.forename: Farideh Z
authors.initials: FZ
authors.lastname: Bischoff
authors.forename: Tony J
authors.initials: TJ
authors.lastname: Pircher