changes in her2status of circulating tumor cells during treatment with herceptin

[Lani]

occur in ~19% of patients, both loss and gain of her2 +ivity in the CTCs while under treatment with herceptin, chemotherapy

Those with her2+ ctcs had worse prognosis than those her2+patients with her2-ctcs or those without ctcs

This study used Cell Search technology, the only one commercially available in the US. There is another technology out of Germany and one which may become available in January (hspeard @ ASCO breast) which uses microfluidic chip technology and so captures cells even if they do not have EPCAM, MUC1, or other biomarkers udrf to magnetically isolate them by the first two technologies listed above

The last technology isolates more CTCs--results with respect to changes in her2 status of ctcs with herceptin status may change if looked at again with different technology. The field is evolving...



Changes of HER2 Status in Circulating Tumor Cells Compared With the Primary Tumor During Treatment for Advanced Breast Cancer
Journal Clinical Breast Cancer
Issue Volume 10, Number 5 / October 2010

Pages 392-397


Authors
Elisabetta Munzone1, Franco Nolé1, Aron Goldhirsch1, Edoardo Botteri2, Angela Esposito1, Laura Zorzino3, Giuseppe Curigliano1, Ida Minchella1, Laura Adamoli1, Maria Cristina Cassatella3, Chiara Casadio3, Maria Teresa Sandri3
1Division of Medical Oncology, European Institute of Oncology, Milan, Italy
2Division of Epidemiology and Biostatistics, European Institute of Oncology, Milan, Italy
3Division of Pathology and Laboratory Medicine, European Institute of Oncology, Milan, Italy

Abstract
Background: HER2/neu status of tumor cells at metastatic sites in patients with advanced disease may differ from that of the primary tumor. Assessing the presence of target antigens on circulating tumor cells (CTCs) might affect treatment choice. Patients and Methods: From June 2007 to October 2008, we collected 23 mL of blood from each of the 76 consecutive patients before and during chemotherapy to determine CTC numbers and HER2 overexpression. CTCs were isolated with the CellSearch System® (Veridex, LLC; Raritan, NJ) and fluorescently stained with the Epithelial Cell Kit®. Tumor Phenotyping Reagent® was used to investigate HER2/neu overexpression. Results: Concordance of HER2 status between the primary tumor and CTCs was 86% (49 out of 57 patients) at baseline and 82% (50 out of 61 patients) in the treatment samples. HER2 overexpression in CTCs was acquired in 8 out of 45 patients (18%) and lost in 3 out of 16 patients (19%) during a treatment containing trastuzumab. The overall discordance rate between the primary tumor and CTCs was 18% (11 out of 61 patients). Patients with HER2 overexpression in CTCs had poorer progression-free survival compared with those without CTCs or with HER2− CTCs (log-rank P =.036). Conclusion: Information on the presence or absence of HER2 overexpression can be obtained in CTCs. Larger trials are needed to evaluate the activity of HER2-targeted therapy in patients with acquired HER2 overexpression in CTCs.