Presentation Authors: John Lam*, David Finley, Stephen Poon, William Sohn, Yu Wang, Philip Kim, Stephen Williams, Eugene Rhee, Ronald Loo, Gary Gochman, Jeffrey Shiffer, Pasadena, CA
Introduction: Genomic markers have been increasingly utilized to assist in the early detection of prostate cancer and an epigenetic assay has been able to identify men who may forego an unnecessary repeat biopsy. This study looked at the value of a second opinion review in positive epigenetic assays in negative histopathological prostate biopsies.
Methods: We evaluated the archived, cancer negative prostate biopsy core tissue samples of 49 subjects from an integrated health care system in Southern California. Biopsy cores were epigenetically profiled for GSTP1, APC and RASSF1 relative to the ACTB reference gene using quantitative methylation specific polymerase chain reaction in patients with rising PSA or increasing clinical suspicion. Predetermined analytical marker cutoffs were used to determine assay performance. DNA methylation positive biopsy cores underwent second opinion review by a pathologist.
Results: The epigenetic assay was performed in 49 cases of negative histopathological prostate biopsy cores, and found to be negative in 32 (65%) cases and positive in 17 (35%) cases. ASAP was present in 3 (6%) cases and HGPIN was present in 2 (4%) cases. Four (24%) of 17 positive cases that underwent second opinion review revealed the presence of prostate cancer. All prostate cancer diagnosed were Gleason score 6. In addition, there were 4 (24%) cases of ASAP and 4 (24%) cases of HGPIN diagnosed.
Conclusions: Second opinion review of a positive epigenetic assay in histopathological negative prostate biopsies resulted in a proportion of cases having the diagnosis of prostate cancer. These results suggest that epigenetic assays can be used to assist with prostate cancer diagnosis and may circumvent need for repeat prostate biopsy or have implications in surveillance strategies.