Abstract P1-11-19: Prognostic Significance of Ki67 Index after Neoadjuvant Chemotherapy for Human Breast Cancer

• Published in: Cancer research (Chicago, Ill.) Vol. 70; no. 24_Supplement; pp. P1 - P1-11-19
• Main Authors: Tanei, T, Shimomura, A, Shimazu, K, Nakayama, T, Kim, SJ, Tamaki, Y, Noguchi, S.
• Format: Journal Article
• Language: English
• Published: 15.12.2010
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/0008-5472.SABCS10-P1-11-19

Abstract Purpose: The Ki67 index (cell proliferation marker) has recently been attracting considerable attention as a prognostic factor in breast cancer, but the prognostic significance of Ki67 after neoadjuvant chemotherapy (NAC) has hardly been studied. Experimental Design: Primary breast cancer patients (n=102) treated with NAC (sequential paclitaxel 12 cycles (q1w) and 5-FU/epirubicin/cyclophosphamide 4 cycles (q3w)) were recruited for this study. In the patients who did not achieve pathological complete response (pCR) after NAC. we evaluated the expression of Ki67, estrogen receptor (ER), progesterone receptor (PR), breast cancer resistant protein (BCRP) and P-glycoprotein were determined by immunohistochemistry, and HER2 was determined by FISH in tumor tissues obtained before and after NAC. Therefore the association of these proteins with patient prognosis (relapse-free survival) was examined. Results: pCR was achieved in 30 (29.4%) of the 102 patients. In the remaining 72 non-pCR patients, the Ki67 index significantly (P<0.001) decreased after NAC, and the Ki67 index after but not before NAC, was significantly associated with patient prognosis (P=0.022). Multivariate analysis showed that the Ki67 index after NAC was a marginally significant (P=0.05) prognostic factor and that other biomarkers including ER, PR, BCRP, and P-glycoprotein either before or after NAC were not significant. Conclusions: Ki67 after but not before NAC, is prognostic for breast cancer patients, and may be clinically useful for the prediction of prognosis for patients who do not achieve pCR after NAC. On the other hand, BCRP and P-glycoprotein either before or after NAC are unlikely to be useful as prognostic factors for such patients. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-11-19.