Promoter Methylation of Protocadherin8 is an Independent Prognostic Factor for Biochemical Recurrence of Early-Stage Prostate Cancer

BACKGROUND Protocadherin8 has been demonstrated to play critical roles in initiation and progression of several human cancers. It is frequently inactivated by promoter methylation in cancers and may be used as a potential biomarker. However, the methylation status of protocadherin8 and its clinical significance in prostate cancer remains largely unknown. The purpose of this study was to evaluate the clinical significance of protocadherin8 methylation in early-stage prostate cancer. MATERIAL AND METHODS The promoter methylation status of protocadherin8 in 162 prostate cancer tissues and 47 normal prostate tissues was examined using methylation-specific PCR (MSP). Subsequently, the relationships between protocadherin8 methylation and clinicopathological features of prostate cancer patients and biochemical recurrence-free survival of patients were analyzed. RESULTS We found that protocadherin8 methylation occurred frequently in prostate cancer tissues but not in normal prostate tissues. Moreover, protocadherin8 methylation was significantly associated with advanced pathologic stage, higher level of preoperative prostate specific antigen (PSA), higher Gleason score, positive lymph node metastasis, and biochemical recurrence. In addition, patients with protocadherin8 methylated have shorter biochemical recurrence-free survival time than patients without. Multivariate Cox regression analysis revealed that protocadherin8 methylation was an independent predictor of biochemical recurrence-free survival in prostate cancer patients. CONCLUSIONS Promoter methylation of protocadherin8 is a frequent event in prostate cancer, and might be used as an independent prognostic factor for biochemical recurrence-free survival in patients with prostate cancer.