The objective of this study is to develop molecular signatures predictive of response to neoadjuvant chemotherapy which would be able to discriminate between patient groups based on their epithelio-mesenchymal transition (EMT) status and their immune status. As these two parameters are known to be responsible for incomplete responses to chemotherapy, investigators hypothesize that these signatures will be predictive of response to neoadjuvant chemotherapy. In a second step, researchers will evaluate the ability of these signatures to predict treatment response in breast cancer patients treated with neoadjuvant chemotherapy.