Predictive markers for chemotherapy response in breast cancer.

More than 13,000 women are diagnosed with breast cancer in the Netherlands each year. 86% of breast cancer patients survive 5 years after diagnosis, however, many patients still succumb to this disease eventually. In addition to surgery, radiation, or targeted therapy (e.g. hormone or growth receptor antagonism), patients with an unfavorable prognosis are usually treated with chemotherapy. To identify the therapy of which an individual patient has most benefit, it is a major goal of molecular oncology to find markers that predict therapy response. Such predictive markers are already common in decisions to prescribe targeted therapy to breast cancer patients. In contrast, markers that predict the tumor response to chemotherapy are elusive. In this study I review different techniques and approaches used to discover markers that predict breast cancer response to different chemotherapy treatments. The advantages and disadvantages of these techniques are discussed and suggestions are made about what could be improved in the future. The hope is that predictive biomarkers can contribute to personalized chemotherapy treatment in breast cancer