Gene expression-based prediction of neodjuvant chemotherapy response in early breast cancer

Prospective, non-comparative Phase II multicenter trial (EXPRESSION EudraCT: 2008-006381-29) where the patients received three 3-week cycles of docetaxel (100 mg/m2) followed by three 3-week cycles of 5-fluorouracil (500 mg/m2), epirubicin (100 mg/m2), and cyclophosphamide (500 mg/m2) (FEC). The primary end point was the identification of a gene expression signature predictive of pathological complete response (pCR). In this trial, pCR was defined as absence of invasive or non-invasive cancer in the breast. External validation of the predictive performance was performed using publicly available data. Pre-treatment core needle biopsies were obtained from primary tumors and stored at -80°C until analysis. RNA was isolated and hybridized to Affymetrix HG U133 plus 2.0 microarrays.