Tau expression and efficacy of paclitaxel treatment in metastatic breast cancer

Purpose Paclitaxel is widely used for the treatment of patients with metastatic breast cancer (MBC). Although several mechanisms of paclitaxel resistance have been demonstrated, useful markers of paclitaxel resistance have not been available in clinical practice. Methods In this study, the clinical significance of tau expression in MBC cases was established by identifying candidates with paclitaxel administration. Tissue specimens obtained from 35 patients were examined. Status of tau expression was determined by immunohistochemistry. Results Fifteen cases were classified as tau-negative and 20 cases were classified as tau-positive, respectively. Sixty percent of tau-negative expression showed favorable response. Conversely, 85% of tau-positive expression showed progressive or stable disease after paclitaxel administration. Time to disease progression in tau-negative and tau-positive groups was 9.4 ± 6.6 and 6.0 ± 3.7 months, respectively. Conclusions Patients with tau-positive expression may derive less benefit than tau-negative from paclitaxel therapy in MBC.