Preoperative p27 status is an independent predictor of prostate specific antigen failure following radical prostatectomy

Purpose: p27 is an important cell cycle regulator, and decreased expression in radical prostatectomy specimens is associated with an increased risk of prostate specific antigen (PSA) failure. To our knowledge no prior study has shown that preoperative p27 status independently predicts recurrence after radical prostatectomy. Materials and Methods: The prostate needle biopsy specimens of 161 men treated with radical prostatectomy were examined for p27 expression using immunohistochemistry. Various p27 cut points were examined for their ability to separate patients into groups with different risk for time to biochemical recurrence following radical prostatectomy. The best p27 cut point was compared to other clinical variables (PSA, clinical stage, age, biopsy Gleason score and percent of prostate needle biopsy with cancer) on multivariate analysis to determine which variables independently predicted biochemical failure. Results: A p27 cut point of less than 45% positive staining cells resulted in significant preoperative risk stratification for time to PSA failure (HR 2.41, p = 0.010). On multivariate analysis serum PSA (HR 1.04, p = 0.011), biopsy Gleason score (HR 1.51, p = 0.011), percent of biopsy tissue with cancer (HR 10.01, p = 0.001) and less than 45% p27 positive cells (HR 2.44, p = 0.014) were all independent predictors of biochemical recurrence. Conclusions: Preoperative p27 expression is an independent predictor of time to biochemical recurrence following radical prostatectomy. Patients with less than 45% p27 positive cells in the prostate needle biopsy specimen have almost a 2.5-fold increased risk of biochemical recurrence. To our knowledge this study is the first to show that p27 status of the prostate needle biopsy specimen can be used before radical prostatectomy to predict biochemical failure.