Prognostic value of circulating tumor cells in primary and metastatic breast cancer

In patients with breast cancer, there is evidence correlating the presence of circulating tumor cells (CTCs) with disease-free survival, progression-free survival and overall survival. The detection of CTCs may be useful in gaining a better understanding of the mechanisms of tumor growth and in the improvement of patient management. This review analyzes the prognostic and predictive relevance of CTCs through the principal published studies, cytometric techniques and nucleic acid-based approaches to detect CTCs, phenotypic expression of specific receptors, molecular pathways and genetic signatures for potential tailored therapies.