The Sentinel Prostate Cancer Platform: Validation Studies
Laurence Klotz, MD, Professor of Surgery at the University of Toronto and the Sunnybrook Chair of Prostate Cancer Research, discusses the Sentinel PCC4 assay for prostate cancer in detail and reviews data on its performance characteristics. He gives an overview of the Sentinel Prostate Disease Management Platform, explaining that it is based on an analysis of a large number of urinary exosomal small non-coding (snc)RNAs that have been found to be predictive of cancer and cancer stage. Dr. Klotz shows an electron microscopy of urinary microvesicles and overviews research that looked at the independent predictive value of around 10,000 different microRNA sequences and ranked them according to the likelihood of being associated with cancer being present or not. 442 of the sequences were selected for further analysis and are used as part of the Sentinel PCC4 assay. He then discusses initial Sentinel Assay data published in the Journal of Urology showing 98% specificity for detecting the presence or absence of cancer and 96% specificity for differentiating low-grade vs. high-grade cancer. This data raised the question of how Sentinel could predict the results of biopsy so well when biopsy does not correlate as closely with the extent and grade of cancer present. Dr. Klotz reviews a summary of the key validation data to date that reveals a specificity rate of 66%, with a 34% rate of false positives, and found that 52% of positive Sentinel assays for any cancer were followed by a negative biopsy. He suggests that this liquid biomarker test is superior to others and that the data is compelling. Dr. Klotz concludes that the Sentinel PCC4 sncRNA assay has high specificity and sensitivity, relatively speaking, and that further validation studies are ongoing.
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