Gene Expression Profiles of Breast Cancer Obtained from Core Cut Biopsies Before Neoadjuvant Docetaxel, Adriamycin, and Cyclophoshamide Chemotherapy Correlate with Routine Prognostic Markers and Could Be Used to Identify Predictive Signatures

Our results demonstrate that reliable expression profiles can be achieved by using limited amounts of tissue obtained during neoadjuvant chemotherapy. Microarray data capture conventional prognostic markers but might contain additional informative gene sets correlated with treatment outcome. Prognostic marker sets are not suitable to predict tumor response in the neoadjuvant setting, suggesting the necessity of class prediction methods to identify marker sets predictive for the type of therapy used.