HER2 status of circulating tumor cells in patients with metastatic breast cancer: a prospective, multicenter trial

Tanja Fehm (1) , Volkmar Müller (2) , Bahriye Aktas (3) , Wolfgang Janni (4) , Andreas Schneeweiss (5) , Elmar Stickeler (6) , Claus Lattrich (7) , Christian R. Löhberg (8) , Erich Solomayer (9) , Brigitte Rack (10) , Sabine Riethdorf (11) , Christoph Klein (12) , Christian Schindlbeck (10) , Kerstin Brocker (5) , Sabine Kasimir-Bauer (3) , Diethelm Wallwiener (13) , Klaus Pantel (11)

1 Department of Gynecology and Obstetrics
2 Department of Gynecology
3 Department of Gynecology and Obstetrics
4 Department of Gynaecology and Obstetrics
5 Department of Gynecology and Obstetrics
6 Department of Gynecology and Obstetrics
7 Department of Gynecology and Obstetrics
8 Department of Gynecology and Obstetrics
9 Department of Gynecology and Obstetrics
10 Department of Gynecology and Obstetrics
11 Institute of Tumor Biology
12 Institute of Pathology, Division of Oncogenomics
13 Department of Gynecology and Obstetrics

There is a growing body of evidence that HER2 status can change during disease recurrence or progression in breast cancer patients. In this context, re-evaluation of HER2 status by assessment of HER2 expression on circulating tumor cells (CTCs) is a strategy with potential clinical application. The aim of this trial was to determine the HER2 status of CTCs in metastatic breast cancer patients comparing two CTC assays. A total of 254 patients with metastatic breast cancer from nine German university breast cancer centers were enrolled in this prospective study. HER2 status of CTCs was assessed using both the FDA-approved CellSearch assay and ™. Using the CellSearch assay, 122 of 245 (50%) patients had ≥5 CTCs, and HER2-positive CTCs were observed in 50 (41%) of these patients. Ninety of 229 (39%) patients were CTC positive using , and HER2 positivity rate was 47% (42 of 90). The rate of breast cancer patients with HER2-negative primary tumors but HER2-positive CTCs was 32% (25 of 78) and 49% (28 of 57) using the CellSearch assay and , respectively. Considering only those patients who had CTCs on both tests ( = 62), concordant results regarding HER2 positivity were obtained in 50% of the patients (31/62) ( = 0.96, κ = −0.006). HER2-positive CTCs can be detected in a relevant number of patients with HER2 negative primary tumors. Therefore, it will be mandatory to correlate the assay-dependent HER2 status of CTCs to the clinical response on HER2-targeted therapies.

Mots clés: Breast cancer; Circulating tumor cells; HER2; Metastasis

Tanja Fehm, Volkmar Müller, Bahriye Aktas, Wolfgang Janni, Andreas Schneeweiss, et al.. HER2 status of circulating tumor cells in patients with metastatic breast cancer: a prospective, multicenter trial. Breast Cancer Research and Treatment, 2010, 124 (2), pp.403-412. ⟨10.1007/s10549-010-1163-x⟩. ⟨hal-00578726⟩