Detection of GSTP1 methylation in prostatic secretions using combinatorial MSP analysis

Abstract

Objectives: To evaluate the utility of methylation-specific polymerase chain reaction analysis of the pi-class glutathione-S-transferase (GSTP1) gene promoter in prostatic secretions for cancer detection and prognostication.

Methods: Prostatic secretions were obtained from a total of 100 radical prostatectomy specimens immediately after surgical extirpation. GSTP1 promoter methylation was assessed by methylation-specific polymerase chain reaction analysis using two different primer sets. Correlations between GSTP1 promoter methylation and clinical and pathologic variables were examined.

Results: The sensitivity for detection of GSTP1 methylation in prostatic secretions from men with clinically localized prostate cancer using two different primer sets was 76% and 54%. Methylation of the GSTP1 promoter was detected by both primer sets in 44% and by at least one primer set in 86% of the prostatic secretion specimens. The degree of methylation detected in the prostatic secretions was associated with the extent of cancer (predominant involvement of one or both sides of the gland; P = 0.02) and increasing age (P = 0.009).

Conclusions: Genomic DNA with GSTP1 promoter methylation can be detected in prostatic secretion specimens from the great majority of men with localized prostate cancer. Assays of GSTP1 promoter methylation in prostatic massage fluid or ejaculate may therefore serve as useful adjuncts to existing methods for prostate cancer screening and prognostication.