The impact of DNA methylation on the identification of recurrent prostate cancer

Abstract

21086 Purpose: Biochemical (PSA) recurrence of prostate cancer following radical prostatectomy remains a major problem. Better biomarkers are needed to identify high and low-risk patients. DNA methylation of promoter regions leads to gene silencing in many cancers. In this study, we assessed the impact of changes in DNA methylation on biochemical recurrence in men with prostate cancer. Methods: We examined the methylation status of fifteen genes using MSP (Methylation Specific PCR) on tissue samples from 151 patients with clinically localized prostate cancer for whom at least five years of follow-up after prostatectomy was available. Results: In a multivariable logistic regression analysis, extra capsular penetration, high Gleason score, and involvement of the lymph nodes, seminal vesicles, or surgical margin were associated with an increased risk of recurrence. In addition, samples with methylation of 2 specific genes involved in cell-cell adhesion and apoptosis were associated with biochemical recurrence with an odds ratio of 5.64 (95% CI=1.47–21.7, p=0.012) compared to samples without methylation of both of these genes. The methylation status of these 2 genes had a higher sensitivity (72.3%; 95% CI=57–84.4%) for detecting recurrences than all the clinico-pathological variables (p<0.02) except extra-capsular penetration (p=0.346). The methylation status of these 2 genes had a similar negative predictive value (79.0%; 95% CI=66.8–88.3%) as the individual clinico-pathological variables examined. Conclusion: DNA Methylation of specific genes is independently associated with an increased risk of biochemical recurrence after radical prostatectomy even one considers the prognostic clinico-pathologic variables used in the clinic today. Our findings should be validated on another larger group of patients with prostate cancer who have undergone radical prosatetectomies. No significant financial relationships to disclose.