Objective: To investigate the impact of androgen receptor splice variant 7 (AR-V7) expression on overall survival for patients with metastatic prostate cancer.
Methods: The data of 113 diagnosed metastatic prostate cancer patients from January 2002 to June 2010 were collected retrospectively, including patient's age at diagnosis, prostate-specific antigen (PSA) level at diagnosis,Gleason score, clinical stage, PSA nadir during hormonal therapy, the time to PSA nadir, vital status, survival time and cause of death. The expression of AR-V7 in prostate cancer tissue was detected by using immunohistochemical staining. The correlation of AR-V7 expression and patient clinicopathological characteristics in all patients were analysed using Student t-test or Chi-square test. Cox proportional hazards regression models were used to evaluate the predictive role of AR-V7 expression and patient characteristics for overall survival.
Results: The median PSA nadir was 0.7 µg/L (ranged from 0.0 to 143.0 µg/L). The median time to PSA nadir was 8.1 months (ranged from 0.9 to 71.0 months). The follow-up was performed until March 12, 2014. During the follow-up period, 67 of 113 metastatic prostate cancer patients (59.3%) died and the median overall survival was 96 months (ranged from 5 to 135 months). The AR-V7 detection rate was 20.4% (23/113). The serum PSA level in patients with positively expression of AR-V7 was significantly higher than that without AR-V7 expression (t = 2.521, P = 0.013). Multivariate Cox regression analysis indicated that the expression of AR-V7 (HR = 2.421, P = 0.002) and time to PSA nadir (HR = 1.019, P = 0.022) were independent prognostic factors of overall survival for metastatic prostate cancer patients.
Conclusions: The expression of AR-V7 in prostate cancer tissues and time to PSA nadir during hormonal therapy are independent prognostic factors of overall survival for metastatic prostate cancer patients. Therapy targeting AR-V7 may improve prognosis of metastatic prostate cancer patients.