title: Detection of circulating tumor cells in breast cancer may improve through enrichment with anti-CD146.
abstract: Most assays to detect circulating tumor cells (CTCs) rely on EpCAM expression on tumor cells. Recently, our group reported that in contrast to other molecular breast cancer subtypes, "normal-like" cell lines lack EpCAM expression and are thus missed when CTCs are captured with EpCAM-based technology [J Natl Cancer Inst 101(1):61-66, 2009]. Here, the use of CD146 is introduced to detect EpCAM-negative CTCs, thereby improving CTC detection. CD146 and EpCAM expression were assessed in our panel of 41 breast cancer cell lines. Cells from 14 cell lines, 9 of which normal-like, were spiked into healthy donor blood. Using CellSearch technology, 7.5 ml whole blood was enriched for CTCs by adding ferrofluids loaded with antibodies against EpCAM and/or CD146 followed by staining for Cytokeratin and DAPI. Hematopoietic cells and circulating endothelial cells (CECs) were counterstained with CD45 and CD34, respectively. A similar approach was applied for blood samples of 20 advanced breast cancer patients. Eight of 9 normal-like breast cancer cell lines lacked EpCAM expression but did express CD146. Five of these 8 could be adequately recovered by anti-CD146 ferrofluids. Of 20 advanced breast cancer patients whose CTCs were enumerated with anti-EpCAM and anti-CD146 ferrofluids, 9 had CD146+ CTCs. Cells from breast cancer cell lines that lack EpCAM expression frequently express CD146 and can be recovered by anti-CD146 ferrofluids. CD146+ CTCs are present in the peripheral blood of breast cancer patients with advanced disease. Combined use of anti-CD146 and anti-EpCAM is likely to improve CTC detection in breast cancer patients.
authors.affiliation: Department of Medical Oncology, Daniel den Hoed Cancer Center and Laboratory of Translational Tumor Immunology, Erasmus MC, Groene Hilledijk 301, 3075 EA Rotterdam, The Netherlands. b.mostert@erasmusmc.nl
authors.forename: Bianca
authors.initials: B
authors.lastname: Mostert
authors.forename: Jaco
authors.initials: J
authors.lastname: Kraan
authors.forename: Joan
authors.initials: J
authors.lastname: Bolt-de Vries
authors.forename: Petra
authors.initials: P
authors.lastname: van der Spoel
authors.forename: Anieta M
authors.initials: AM
authors.lastname: Sieuwerts
authors.forename: Mieke
authors.initials: M
authors.lastname: Schutte
authors.forename: Annemieke M
authors.initials: AM
authors.lastname: Timmermans
authors.forename: Renée
authors.initials: R
authors.lastname: Foekens
authors.forename: John W M
authors.initials: JW
authors.lastname: Martens
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: Gratama
authors.forename: John A
authors.initials: JA
authors.lastname: Foekens
authors.forename: Stefan
authors.initials: S
authors.lastname: Sleijfer
mesh_terms: D000328:Adult; D018952:Antigens, CD34 / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology*; D051929:CD146 Antigen / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D019937:Diagnostic Techniques and Procedures; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D055815:Young Adult
chemical_list: D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D051929:CD146 Antigen; D012333:RNA, Messenger