Single circulating tumor cell profiling: a new perspective for targeted therapy?

Evaluation of: Powell AA, Talasaz AH, Zhang H et al. Single cell profiling of circulating tumor cells: transcriptional heterogeneity and diversity from breast cancer cell lines. PLoS ONE 7(5), e33788 (2012). Circulating tumor cells (CTCs) may represent a possible useful tool to better define the prognosis of patients. The presence of CTCs can help to predict an increased risk for disease relapse, and they might be an early marker for treatment efficacy that could help in deciding treatment continuation. Cancer metastasis occurs when cells, shed from the primary tumor, enter the circulation and begin to grow in distant locations around the body. In metastatic stages, shed cells may differ from those of the primary tumor, as the tumor phenotype can change during the course of the disease. It is important to identify relevant targets expressed on these cells to provide clinical information on therapy choice, efficacy and drug resistance. Many efforts are now devoted to the characterization of the single cell. This article focuses on the possibility of profiling single CTCs in patients with breast cancer.