Unbiased quantitative assessment of Her-2 expression of circulating tumor cells in patients with metastatic and non metastatic breast cancer

Jean-Yves Pierga, Sjoerd Ligthart, François-Clement Bidard, Charles Decraene, Thomas Bachelot, Suzette Delaloge, Etienne Brain, Mario Campone, Patrice Viens, Leon W.M.M. Terstappen

Research output: Contribution to conferencePaper

Abstract

Circulating tumor cells (CTC) can provide the basis for a real-time liquid biopsy and may guide the use of targeted therapies. We report on unbiased quantification of Her-2 protein expression of CTC. Her-2 assessment of CTC was performed using the CellSearch® system in 103 metastatic (M1) and 88 non metastatic (M0) breast-cancer patients. Digital images of Cytokeratin-PE, DAPI, CD45-APC, and Her-2-FITC from these samples were stored. Expression of Her-2 on CTC was determined by manual review and an automated algorithm using Her-2-FITC fluorescence of leukocytes to determine the Her-2-expression threshold in each sample. Her-2 expression of CTC varied greatly within and between patients compared to Her-2 expression of leukocytes. In M1 patients, a threshold of 75% of Her-2 positive CTC in patients with >5 CTC showed a relatively low discrepancy rate between the primary tumor and CTC Her-2 status. Applying this threshold, 9% of M1 patients with Her-2 negative primary tumors had Her-2 positive CTC status and 29% of M1 patients with Her-2 positive primary tumors had Her-2 negative CTC status. No Her-2 discrepancy was observed between CTC and primary tumor in M0 patients. Our findings demonstrate the feasibility of real-time quantitative and reproducible assessment of treatment targets on CTC, opening a path towards personalized treatment. Her-2 expression is heterogeneous among CTC within each patient. Overall, M1 patients with Her-2 positive primary tumors exhibited Her-2 negative CTC frequently, whereas discrepancies in Her-2 status were limited in other clinical settings.
Original languageEnglish
DOIs
Publication statusPublished - 31 Mar 2012
Event103rd AACR Annual Meeting 2012 - Chicago, United States
Duration: 31 Mar 20124 Apr 2012
Conference number: 103

Conference

Conference103rd AACR Annual Meeting 2012
CountryUnited States
CityChicago
Period31/03/124/04/12

Keywords

  • METIS-298084

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    Pierga, J-Y., Ligthart, S., Bidard, F-C., Decraene, C., Bachelot, T., Delaloge, S., ... Terstappen, L. W. M. M. (2012). Unbiased quantitative assessment of Her-2 expression of circulating tumor cells in patients with metastatic and non metastatic breast cancer. Paper presented at 103rd AACR Annual Meeting 2012, Chicago, United States. https://doi.org/10.1158/1538-7445.AM2012-2368