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 language | English |
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DOIs | |
Publication status | Published - 31 Mar 2012 |
Event | 103rd AACR Annual Meeting 2012 - Chicago, United States Duration: 31 Mar 2012 → 4 Apr 2012 Conference number: 103 |
Conference
Conference | 103rd AACR Annual Meeting 2012 |
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Country/Territory | United States |
City | Chicago |
Period | 31/03/12 → 4/04/12 |
Keywords
- METIS-298084