Detection of circulating tumor cells in breast cancer may improve through enrichment with anti-CD146

Bianca Mostert (1, 2) , Jaco Kraan (1) , Joan Bolt-de Vries (2) , Petra Spoel (1) , Anieta M. Sieuwerts (2) , Mieke Schutte (3) , Annemieke M. Timmermans (2) , Renée Foekens (2) , John W. M. Martens (2) , Jan-Willem Gratama (1) , John A. Foekens (2) , Stefan Sleijfer (1, 2)

1 Department of Medical Oncology, Daniel den Hoed Cancer Center and Laboratory of Translational Tumor Immunology
2 Department of Medical Oncology, Josephine Nefkens Institute and Cancer Genomics Center
3 Department of Medical Oncology, Josephine Nefkens Institute and Laboratory of Tumor Biology and Pharmacogenomics

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.

Mots clés: Circulating tumor cells; Breast cancer; CellSearch; CD146; Minimal residual disease; EpCAM

Bianca Mostert, Jaco Kraan, Joan Bolt-de Vries, Petra Spoel, Anieta M. Sieuwerts, et al.. Detection of circulating tumor cells in breast cancer may improve through enrichment with anti-CD146. Breast Cancer Research and Treatment, 2010, 127 (1), pp.33-41. ⟨10.1007/s10549-010-0879-y⟩. ⟨hal-00594475⟩