Measuring β‐tubulin III, Bcl‐2, and ERCC1 improves pathological complete remission predictive accuracy in breast cancer

Weekly PCb (paclitaxel + carboplatin) in neoadjuvant chemotherapy (NCT) for breast cancer has a high pathological complete remission (pCR) rate. The present study was to identify pCR predictive biomarkers and to test whether integrating candidate molecular biomarkers can improve the pCR predictive accuracy. Ninety‐one breast cancer patients treated with weekly PCb NCT were retrospectively analyzed. Eleven candidate molecular biomarkers (Tau, β‐tubulin III, PTEN, MAP4, thioredoxin, multidrug resistance‐1, Ki67, p53, Bcl‐2, BAX, and ERCC1) were detected by immunohistochemistry in pre‐NCT core needle biopsy specimens. We analyzed the relationship between these biomarkers and pCR. Univariate analysis showed that estrogen receptor, progesterone receptor, molecular classification (clinicopathological markers), and Tau, β‐tubulin III, p53, Bcl‐2, ERCC1 (candidate molecular biomarkers) expression were associated with pCR rate; however, multivariate analysis revealed that only β‐tubulin III, Bcl‐2, and ERCC1 were independent pCR predictive factors. Patients with β‐tubulin III negative, Bcl‐2 negative, or ERCC1 negative tumors were associated with higher pCR rate, with OR (odds ratios) 6.03 (95% confidence interval [CI], 1.44–25.24, P = 0.014), 7.54 (95% CI, 1.52–37.40, P = 0.013), and 4.09 (95% CI, 1.17–14.30, P = 0.028), respectively. To compare different logistic regression models, built with different combinations of these variables, we found that the model integrating routine clinical and pathological variables, as well as the β‐tubulin III, Bcl‐2, ERCC1 molecular biomarkers had the highest pCR predictive power. The area under the ROC curve for this model was 0.900 (95% CI, 0.831–0.968), indicating that it deserves further investigation. Trial name: Weekly Paclitaxel Plus Carboplatin in Preoperative Treatment of Breast Cancer. (Cancer Sci 2012; 103: 262–268)