Breast circulating tumor cells: Potential biomarkers for breast cancer diagnosis and prognosis evaluation

Abstract

Circulating tumor cells (CTCs) have been considered an indicator of tumor invasion. CTCs have recently been detected in breast cancer patients and have become a target for evaluating breast cancer progression, prognosis, and diagnosis. CTCs are a heterogenous population with phenotypes ranging from epithelial to mesenchymal. CTCs express various markers including epithelial cell adhesion molecule, cytokeratins, and MUC-1, depending on the stage of epithelial-mesenchymal transition. Breast CTCs are usually detected and confirmed via two steps, including enrichment and identification. These methods have become powerful tools for diagnosis and for predicting response to systemic therapies. This chapter aims to review breast CTC biology and the role of CTC detection in breast cancer prognosis and diagnosis. Recent advances in CTC research mean that CTCs are becoming a strong tool for the prognosis and diagnosis of breast cancer.