 Neoadjuvant chemotherapy is frequently proposed to patients with mammary gland cancer. The aim is to reduce tumor volume before surgical therapy. Obtaining a pathologic Complete Response pCR is regarded as a good prognostic factor with less risk of recurrence. The rate of pCR is about 20, although there are important variations according to tumor subtype and the type of treatment. The objective of the new therapeutic strategies is to increase this response rate. 