NEW ORLEANS, LA USA (UroToday.com) - In this talk, Dr. James D. Brooks of Stanford University discussed the use of genomic profiling in the diagnosis and risk stratification of prostate cancer. He began with an overview of the tests available in the clinic today. The examination of the transcriptome is furthest along at this point in prostate cancer. He highlighted the ability of the detection of the TMPRSS2-ERG fusion transcript in urine to identify patients at higher risk for the presence of prostate cancer. He stated that PCA3, as well as AMACR, which is widely used by pathologists for prostate cancer diagnosis, were discovered by a genomics approach.
Beyond just the diagnosis of prostate cancer, Dr. Brooks discussed that Oncotype DX and Prolaris both utilize expression profiling for the determination of prognosis. Long-non-coding RNA SChLAP1 in the urine has been shown to be associated with aggressive prostate cancer. He pointed out that these tests highlight the recent success of transcript profiling research in prostate cancer. With regards to whether these successes translate to significant improvements in clinical care however, Dr. Brooks stated that further investigation was necessary. He then moved on to DNA methylation profiling. Assessment of gene methylation profiles via tissue-based assays may aid in prostate cancer diagnosis. He pointed out that in kidney cancer, use of methylation profiling has been shown to accurately diagnose cancer, regardless of histologic subtype.
Focusing next on DNA mutations, Dr. Brooks said that in contrast to other malignancies, very few recurrent or targetable mutations are found in prostate cancer. In addition, DNA rearrangements occur via multiple simultaneous events over a short period of time, termed punctuated evolution by Dr. Brooks. These facts hamper the development of an effective mutation-based biomarker. Sampling error due to intratumoral heterogeneity compounds these issues further. The potential for rapid evolution of a tumor also likely limits long-term therapeutic efficacy. Dr. Brooks concluded that genomic profiling in prostate cancer has evolved rapidly and has resulted in a plethora of promising biomarkers. He noted that sequencing is becoming more and more economical and some day performance of genomic profiling of host or tumors will become routine. A better understanding of the technology and its role in the clinics is necessary prior to its widespread use.
Presented by James D. Brooks, MD at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
Stanford University, Stanford, CA USA
Reported by Timothy Ito, MD, medical writer for UroToday.com