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ABSTRACT: Background
Preclinical and clinical studies have reported that human epidermal growth factor receptor 2 (HER2) overexpression yields resistance to endocrine therapies. Here the prevalence and prognostic impact of HER2-positive circulating tumor cells (CTCs) were investigated retrospectively in metastatic breast cancer (MBC) patients with a HER2-negative primary tumor receiving endocrine therapy. Additionally, the prevalence and prognostic significance of HER2-positive CTCs were explored in a chemotherapy cohort, as well as the prognostic impact of the estrogen receptor (ER) CTC status in both cohorts.Methods
Included were MBC patients with a HER2-negative primary tumor, with ?1 detectable CTC, starting a new line of treatment. CTCs were enumerated using the CellSearch system, characterized for HER2 with the CellSearch anti-HER2 phenotyping reagent, and characterized for ER mRNA expression. Primary end point was progression-free rate after 6 months (PFR6months) of endocrine treatment in HER2-positive versus HER2-negative CTC patients.Results
HER2-positive CTCs were present in 29% of all patients. In the endocrine cohort (n=72), the PFR6months was 53% for HER2-positive versus 68% for HER2-negative CTC patients (P=.23). In the chemotherapy cohort (n=82), no prognostic value of HER2-positive CTCs on PFR6months was observed either. Discordances in ER status between the primary tumor and CTCs occurred in 25% of all patients but had no prognostic value in exploratory survival analyses.Conclusion
Discordances regarding HER2 status and ER status between CTCs and the primary tumor occurred frequently but had no prognostic impact in our MBC patient cohorts.
SUBMITTER: Beije N
PROVIDER: S-EPMC5071539 | biostudies-literature | 2016 Nov
REPOSITORIES: biostudies-literature
Beije Nick N Onstenk Wendy W Kraan Jaco J Sieuwerts Anieta M AM Hamberg Paul P Dirix Luc Y LY Brouwer Anja A de Jongh Felix E FE Jager Agnes A Seynaeve Caroline M CM Van Ngoc M NM Foekens John A JA Martens John W M JW Sleijfer Stefan S
Neoplasia (New York, N.Y.) 20161017 11
<h4>Background</h4>Preclinical and clinical studies have reported that human epidermal growth factor receptor 2 (HER2) overexpression yields resistance to endocrine therapies. Here the prevalence and prognostic impact of HER2-positive circulating tumor cells (CTCs) were investigated retrospectively in metastatic breast cancer (MBC) patients with a HER2-negative primary tumor receiving endocrine therapy. Additionally, the prevalence and prognostic significance of HER2-positive CTCs were explored ...[more]