Genomic Signatures to Predict Treatment Response

Inclusion Criteria: * Clinical status of lymph nodes must be available * Sonographical status of lymph nodes must be available * Patients must consent to documentation of cancer treatment * Histologic diagnosis of invasive breast cancer, clinical stage T1-4, M0 (non-inflammatory T4c) * Patients scheduled for neoadjuvant chemotherapy * Treatment with a 3-weekly FEC or AC regimen (3-4 cycles) followed by 3-4 cycles of q3 weekly docetaxel or paclitaxel. * Local HER2 status of tumor biopsy must be negative. Exclusion Criteria: * The patient has a prior history of invasive or metastatic breast cancer. * The patient had prior excisional biopsy of the primary invasive breast cancer. * The patient had prior ipsilateral sentinel axillary lymph node biopsy for breast cancer. * The patient cannot safely or feasibly undergo biopsy of the primary tumor. * The patient has a diagnosis of Stage IV (distant metastatic) breast cancer. * The patient has proven HER2-positive breast cancer, defined as a pathology report of amplification of the gene or 3+ score for immunohistochemical staining.