Heterogeneity of Estrogen Receptor Expression in Circulating Tumor Cells from Metastatic Breast Cancer Patients

Abstract

CTCs frequently lack ER expression in metastatic breast cancer patients with ER-positive primary tumors and show a considerable intra-patient heterogeneity, which may reflect a mechanism to escape endocrine therapy. Provided single cell analysis did not support a role of ESR1 mutations in this process.