Beta-tubulin III expression in prostate cancer

Abstract

Objective. Beta-tubulin isotype III is a microtubule component associated with resistance to chemotherapy and poor outcome in various cancers. This study aimed to investigate its expression in prostate cancer and its role as a prognostic factor in this setting. Material and methods. A tissue microarray was constructed of 289 prostate cancers from radical prostatectomy specimens with a median follow-up of 48.9 months. Slides were immunostained for β-tubulin III. The intensity and extent of immunoreactivity and their product [immunoreactivity product (IRP)] were evaluated. Results. Tubulin III was expressed in the cytoplasm of prostate cancer cells but not in benign glands. Only 11.6% of cancers were positive for tubulin III. Among low-grade (Gleason score 5–6) and high-grade (Gleason score 7–10) cancers, 6.0% and 16.6% were positive, respectively (p = 0.006). β-Tubulin III expression was more often seen in high-stage disease and more often in metastases (62.5%) than in primary lesions (11.6%) (p < 0.001). The intensity, extent and IRP of tubulin III all predicted biochemical recurrence in univariate Cox analysis (p = 0.02, p = 0.048 and p = 0.012, respectively). IRP was an independent predictor of prognosis when adjusted for serum prostate-specific antigen in a multivariate Cox analysis (p = 0.005), but not when the Gleason score was added to the model (p = 0.17). Conclusion. β-Tubulin III predicts biochemical recurrence after radical prostatectomy in a subset of patients. Its practical utility is limited by the low number of cases positive for this biomarker.

Key Words::

• Human
• immunohistochemistry
• pathology
• prostatic neoplasms
• β-tubulin III

Acknowledgements

This work was partially supported by the Ligue contre le Cancer, the Association pour la Recherche contre le Cancer (ARC) and the Swedish Cancer Society.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.