The neoadjuvant setting is especially attractive for studies of predictive biologic correlates for several reasons including early assessment of response to therapy, access to the primary tumor, and reduced patient numbers compared to those required in the adjuvant setting. Response to neoadjuvant therapy is a validated surrogate marker for improved survival; it may be used to test the overall efficacy of neoadjuvant treatment regimens and response in the primary tumor mirrors the effect of therapy on micrometastases.