 The study combines bevacizumab with a very efficacious combination chemotherapy regimen for the treatment of stage II or stage III primary breast cancer. Safety of the TAC-bevacizumab combination will be evaluated. In addition, the study design incorporates an initial cycle of bevacizumab or placebo alone. Assessing the isolated effects of bevacizumab in a setting where pre- and post-treatment tissue specimens can be obtained will provide essential information about the mechanisms by which VEGF inhibition affects tumor growth, and represents an ideal opportunity to evaluate the molecular effects of bevacizumab on breast tumor tissue. 