β3-tubulin is a good predictor of sensitivity to taxane-based neoadjuvant chemotherapy in primary breast cancer.

The objective of this study was to explore the relationship between β3-tubulin expression and sensitivity to taxane-based neoadjuvant chemotherapy in primary breast cancer patients. A total of 48 local advanced breast cancer patients that received taxane-containing neoadjuvant chemotherapy were studied. The levels of β3-tubulin expression were tested by immunohistochemistry before chemotherapy and at the end of cycles 2, 4 and 6. The correlation between the efficacy of the chemotherapy and β3-tubulin expression and changes in β3-tubulin expression over the course of chemotherapy was examined. β3-tubulin protein expression before chemotherapy was significantly and negatively correlated with the response rate. The overall response rate was 31.8 % in the high β3-tubulin expression group, whereas it was 84.6 % in the low β3-tubulin expression group. At the end of cycles 2, 4 and 6 during the treatment course, the average expression rates of β3-tubulin were showed an increasing trend with β3-tubulin expression level at the end of cycle 4 being significantly different from that before chemotherapy. Nine patients that had a low β3-tubulin expression level preneoadjuvant chemotherapy changed to a high β3-tubulin expression level postneoadjuvant chemotherapy, and they had lower response rate than patients with consistent low. In conclusion, β3-tubulin is a good predictor of chemosensitivity to taxane for breast cancer, and the change of its expression level during chemotherapy may be an important cause of secondary resistance to taxane. Detection of β3-tubulin expression before and throughout the chemotherapy will help with selection of the chemotherapy treatment plan.