The use of a panel of monoclonal antibodies to enrich circulating breast cancer cells facilitates their detection.
OBJECTIVE
Metastatic relapse due to early dissemination of tumor cells is associated with poor prognosis for epithelial cancer. The molecular characterization of these single cells or cell clusters that have evaded the tumor is indispensable in order to evaluate their biological behavior and metastatic potential. In this study, we established a sensitive immunomagnetic method to isolate rare cancer cells from peripheral blood based on their expression of epithelial- or tumor-cell-specific markers.


METHODS
Low numbers of cells of breast cancer cell lines - ZR-75-1, MCF-7, HBL-100 - were spiked into peripheral blood specimens of healthy volunteers. Enrichment of tumor cells was performed using either pre-coupled HEA and/or ErbB2 microbeads or a mixture of three monoclonal antibodies against HEA, ErbB2 and EGFR.


RESULTS
The recovery rate of spiked tumor cells correlated with the expression of the corresponding antigens. ZR-75-1 cells high expressing all three genes could be isolated to 60-71%. MCF-7 cells, which hardly express EGFR, showed a significant better recovery by using two specific antibodies in combination (50-68%) than one pre-coupled bead alone (31-42%). HBL-100 cells little expressing HEA could not be isolated with HEA microbeads and only to 27% in combination with ErbB2 beads -in contrast the use of an antibody cocktail achieved 38%.


CONCLUSIONS
As tumor and epithelial specific cell marker antigens are expressed differently in disseminated tumor cells, the immunomagnetic enrichment from peripheral blood is most robust and reliable when using a combination of specific antibodies compared to single antibodies.
Hager
Gudrun
G
Division of Gynaecology, Department of Obstetrics and Gynaecology, Molecular Oncology Group, Medical University of Vienna, Waehringer Guertel 18-20, 5Q A-1090 Vienna, Austria.
Cacsire-Castillo Tong
Dan
D
Schiebel
Ingrid
I
Rezniczek
Günther A
GA
Watrowski
Rafal
R
Speiser
Paul
P
Zeillinger
Robert
R
D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000096:biosynthesis / Q000276:immunology; D001943:Breast Neoplasms / Q000097:blood* / Q000276:immunology / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis / Q000276:immunology; D045744:Cell Line, Tumor; D000071858:Epithelial Cell Adhesion Molecule; D066246:ErbB Receptors / Q000096:biosynthesis / Q000276:immunology; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D008863:Microspheres; D009360:Neoplastic Cells, Circulating / Q000276:immunology / Q000473:pathology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases; C499379:EPCAM protein, human