Immunomagnetic tumor cell selection--implications for the detection of disseminated cancer cells.
BACKGROUND
The optimal method for the detection of disseminated epithelial cancer cells has not yet been found. The standard method, using immunocytochemistry, offers a sensitivity of up to 10(-6). Molecular methods such as cytokeratin-19 RT-PCR are about 10 times as sensitive, but they are hampered by interference such as illegitimate gene expression.


METHODS
Immunomagnetic bead selection of epithelial cancer cells using conjugates directed against the human epithelial antigen (HEA) followed by immunocytochemistry testing was investigated in this trial.


RESULTS
No cytokeratin-positive cells could be enriched from 56 control samples. In 104 clinical samples of bone marrow aspirations, PBPC collections, and venous blood obtained from breast cancer patients, the cytokeratin-positive rate increased significantly, from 29.9 percent before selection to 54.8 percent after enrichment. Even the yield of detected cancer cells was significantly higher after selection. Up to 2.5 x 10(8) MNCs were easily processed. However, the mean cancer cell recovery after HEA enrichment was only 24.4 percent. Subsequently, selected epithelial cells were successfully immunophenotyped by use of a double-stain technique detecting cytokeratin-positive cells and the urokinase-like plasminogen activator receptor.


CONCLUSIONS
HEA bead selection in combination with the standard immunocytochemistry method is a powerful and specific tool for the detection of disseminated cancer cells without false-positive results. Furthermore, it delivers enough cells for subsequent investigations such as characterization studies.
Krüger
W
W
Bone Marrow Transplantation Center, Department of Transfusion Medicine, University Hospital Eppendorf, Hamburg, Germany. krueger@uke.uni-hamburg.de
Datta
C
C
Badbaran
A
A
Tögel
F
F
Gutensohn
K
K
Carrero
I
I
Kröger
N
N
Jänicke
F
F
Zander
A R
AR
D000954:Antigens, Surface / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood; D001943:Breast Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018189:Immunomagnetic Separation; D000951:Antigens, Neoplasm
D000954:Antigens, Surface; D014408:Biomarkers, Tumor; C115012:human epithelial antigen-125; D000951:Antigens, Neoplasm