Epigenetic field effect markers as indicative of occult high-grade prostate cancer.

116 Background: Epigenetic changes through DNA methylation can serve as biomarkers for the presence of prostate cancer (PCa). Gene methylation in histologically benign tissue adjacent to PCa can provide “field effect" biomarkers to detect cancer missed due to sampling errors. Such errors may also result in underestimates of PCa stage or grade, complicating decisions about Active Surveillance. We previously showed increased field effect methylation in GS 7 over GS 6 subjects in a small patient cohort. Here, established methylation markers of PCa (GSTP1, APC and RASSF1) were tested in a larger cohort to compare histologically benign biopsy cores from patients diagnosed with no cancer, low volume GS 6 cancer and GS 7 cancer. The objective was to confirm that epigenetic field effects may be useful for detecting occult high grade malignancies in diagnostic and prognostic settings. Methods: DNA was extracted from prostate biopsy tissue prints and used for multiplex methylation-specific PCR (MSP) assays of the 3...