Circulating tumor cells in breast cancer.

Detection of disseminated tumor cells (DTCs) in bone marrow and of circulating tumor cells (CTCs) in the blood has become a major focus of translational cancer research. DTC presence is a common phenomenon seen in 30-40% of primary breast cancer patients and is strongly associated with poor clinical outcome. Since bone marrow biopsy is an invasive procedure, evaluation of CTCs might become a desired alternative. Recent clinical trials have shown CTC detection to be a promising prognostic tool in both primary and metastatic setting. Evaluation of CTCs might be useful for therapy monitoring and their characterization might help to identify novel targets for biological therapies aimed at disrupting earliest steps of metastatic cascade.