Tissue and soluble biomarkers in breast cancer and their applications: ready to use?

Breast cancer therapies are in continuous evolution: From surgery to hormonal therapy, from classical and new combined chemotherapies to emerging targeted agents of recent introduction to the clinic. The attempt to personalize the best treatment for each patient is driven by efficacy and safety parameters and tumor biology investigations of markers for aggressiveness and response to treatment. The plethora of targeted therapies has provided momentum for the quest to better understand not only target mechanisms of action, but also tumor behavior. Moreover, how to monitor response to these agents is crucial today to achieve better resource-sharing and to find cheaper, less invasive, and standardized detection techniques for clinically validated biomarkers. In this report, we briefly summarize data on the major tissue and soluble biomarkers focusing on their actual use in daily practice, as well as their emerging role and possible future applications in breast cancer treatment.