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 beta 3-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 beta 3-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 beta 3-tubulin expression and changes in beta 3-tubulin expression over the course of chemotherapy was examined. beta 3-tubulin protein expression before chemotherapy was significantly and negatively correlated with the response rate. The overall response rate was 31.8 % in the high beta 3-tubulin expression group, whereas it was 84.6 % in the low beta 3-tubulin expression group. At the end of cycles 2, 4 and 6 during the treatment course, the average expression rates of beta 3-tubulin were showed an increasing trend with beta 3-tubulin expression level at the end of cycle 4 being significantly different from that before chemotherapy. Nine patients that had a low beta 3-tubulin expression level preneoadjuvant chemotherapy changed to a high beta 3-tubulin expression level postneoadjuvant chemotherapy, and they had lower response rate than patients with consistent low. In conclusion, beta 3-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 beta 3-tubulin expression before and throughout the chemotherapy will help with selection of the chemotherapy treatment plan.