Expression of vascular endothelial growth factor and proliferation marker MIB1 are influenced by neoadjuvant chemotherapy in locally advanced breast cancer.

Neoadjuvant chemotherapy (NACT) has become the standard of care for patients with locally advanced breast cancer (LABC). This was a retrospective review of 21 consecutive women who received NACT as initial treatment of LABC, followed by surgical excision. The pre- and post-treatment breast specimens and post-treatment axillary lymph nodes with metastases were immunostained to evaluate for proliferative index (PI) (MIB-1 Immunotech) and vascular endothelial growth factor (VEGF) expression (Santa Cruz, CA, clone A-20). Thirteen of the 21 patients (62%) had more than 50% tumor shrinkage following NACT. The breast's mean PI decreased from 47.86% to 23.95% after treatment (P = 0.005). The mean PI in the post-treatment lymph nodes was 24.47%. A nodal post-NACT PI of less than 10% and progesterone receptor-positive tumor status were associated with better survival, as all such patients are alive. A high PI after NACT was associated with recurrence or death. All of the patients who showed an excellent clinical response had either a decrease in the PI or an absence of a high level of VEGF after NACT. Most patients exhibited persistent expression of VEGF after NACT. Pathologic response in the primary tumor did not correlate with the response in the lymph nodes or with overall survival. NACT reduces the size and PI of the primary breast tumor independent of the patient's node status. The PI may be an early means by which to identify tumors most likely to reduce in size with chemotherapy. A low PI after NACT is associated with better survival. There is persistent expression of VEGF in post-NACT residual breast carcinoma. Thus, anti-VEGF drugs after conventional chemotherapy may benefit patients with residual carcinoma.