Abstract: Background and purpose: Loss of the tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is one of the most common somatic genetic aberrations in prostate cancer in Western countries and is frequently associated with tumor progression and poor prognosis. This study aimed to investigate the frequency of PTEN protein loss in Chinese prostate cancer patients and to determine its association with the biochemical recurrence of prostate cancer. Methods: The data from 225 diagnosed localized prostate cancer patients with radical prostatectomy from 2006 to 2011 were collected retrospectively, including patient’s age at diagnosis, prostate-specific antigen (PSA) level at diagnosis, Gleason score, clinical stage, surgical margin, and time to biochemical recurrence or not. This study performed PTEN protein immunohistochemistry on tissue microarrays, which were made from 225 Chinese prostate cancer patients mentioned above, treated by radical prostatectomy with one case including 2 cancer spots and 2 adjacent normal gland spots. Correlations of PTEN loss with clinicopathological features were analyzed using χ² test. Kaplan-Meier survival model and Cox proportional hazards regression model were used to evaluate the predictive role of PTEN protein expression and patient characteristics for biochemical recurrence. Results: PTEN protein loss was observed in 15% of the patients and was associated with increased preoperative PSA levels (P=0.03) and old age (P=0.009). In univariate Kaplan–Meier analysis, the factors associated with the biochemical recurrence of prostate cancer included PSA levels (P=0.000 4), Gleason sum (P=0.019 8), and PTEN status (P=0.013 1). In multivariable Cox regression analysis, PTEN expression (HR=0.536, P=0.044), PSA levels (HR=1.879, P=0.001), and Gleason score (HR=1.361, P=0.03) were significant in predicting biochemical recurrence of prostate cancer. Conclusion: PTEN protein loss is associated with an increased risk of recurrence, independent of known clinicopathological factors.

Key words: Prostate cancer, Phosphatase and tensin homolog deleted on chromosome 10, Prognosis, Biochemical recurrence, Immunohistochemistry