CK5/6, EGFR, Ki-67, cyclin D1, and nm23-H1 protein expressions as predictors of pathological complete response to neoadjuvant chemotherapy in triple-negative breast cancer patients

The purpose of this study was to evaluate the importance of biological markers to predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) in patients with locally advanced triple-negative breast cancers (TNBCs). Forty-one patients (18.6%) among 220 breast cancer patients were identified as TNBCs from March 2006 to 2009 were included in this prospective study. The pre-NCT treatment expression levels of Ki-67 proliferation index, estrogen receptor (ER), progesterone receptor (PgR), epidermal growth factor receptor 2 (HER-2), CK5/6, epidermal growth factor receptor (EGFR), cyclin D1, and nm23-H1 were detected by immunohistochemistry (IHC). A total of 180 cycles were administered with the median number of four cycles per patient (range, 4-6). The pCR rate was 34.1% (95% CI, 19.6-48.6%). In univariate analysis, early T stage, clinical response after 2 cycles, negative basal-like, negative EGFR, high Ki-67 proliferation index, and positive nm23-H1 were found to be significantly predictive of a pCR (P = 0.010, 0.040, 0.007, 0.001, 0.019, and 0.010, respectively). Basal-like status and nm23-H1 status were significant for pCR on multivariate analysis (P = 0.004 and 0.031, respectively). Basal-like status and nm23-H1 are independent predictive factors of pCR to neoadjuvant docetaxel plus epirubicin combination chemotherapy in patients with TNBCs.