As far as we know, no one has yet come up with a better mousetrap. This is also true of screening tests for prostate cancer (PCa). As everyone knows, the current PSA (prostate specific antigen) blood test is not specific for PCa. It only registers increased activity/irritation of the gland. Yes, it could mean cancer, but it could mean a lot of other conditions as well. It’s not a great mousetrap for PCa.
However, it may be that a company called miR Scientific, LLC has now come up with a better (i.e., more accurate) and completely noninvasive test to detect PCa—and it involves only collecting a urine sample. It is called the miR SentinelTM. If it’s truly as good as claimed, the world of doctors may well beat a path to the company’s door.
According to a July 13, 2022 press release issued by miR Scientific, “miR Sentinel™ is a novel, urine-based, molecular test that analyzes small non-coding RNA using a proprietary biostatistical algorithm. The miR Sentinel™ Test assesses the risk of aggressive prostate cancer and is intended to aid in the clinical management of men >45 years of age at risk for prostate cancer.” Wow! It can both detect PCa and classify it according to aggressiveness? This is certainly above and beyond an ordinary PSA test!
How does it work?
Urine contains very tiny bodies called exosomes. All cells, including cancer cells, manufacture them inside the cell, then release them into circulation so they can be taken up by other cells. Each exosome acts like a packet of molecular instructions in the form of RNA. Exosomes from cancer cells act as biomarkers because their RNA holds tumor-specific instructions. Thus, if PCa is present in the gland, exosomes from tumor cells will be excreted into urine as it passes through the prostate. These can then be isolated from a urine sample and analyzed; thus, the miR Sentinel can calculate the presence and aggression level of PCa, using a proprietary algorithm.
How well does it work?
An initial paper on the development of the miR Sentinel and its prediction algorithm was published in the Journal of Urology in September, 2020.[i] Results of training the algorithm and testing it on urine specimens showed sensitivity of 94% and specificity of 92%. Following that, a multi-center study of roughly 1100 men was presented at the 2022 annual meeting of the American Urological Association. The press release states that the miR Sentinel “…was shown to identify molecular evidence of prostate cancer in at-risk men with 98.5% sensitivity and distinguish clinically non-significant (nominally No Pathological Evidence of Prostate Cancer and Grade Group 1), from clinically significant prostate cancer (nominally Grade Groups 2-5) with a prognostic sensitivity of 83% .” Double wow!
Does this mean no more biopsies?
We recently posted an update to an earlier blog in which we asked, “When will we have a liquid biopsy?” The manufacturer, miR Scientific, notes on its website, “miR is the first peer-reviewed liquid biopsy urine test that accurately detects, classifies, and monitors prostate cancer.” In our blog, we suggest that the term “liquid biomarker analysis” is a more precise descriptor than liquid biopsy. While tests like the miR Sentinel appear highly superior to PSA in terms of detection and indication of aggression level, it’s not advisable to plan treatment without the exact diagnostic information obtained by combining imaging (3T multiparametric MRI) and pathology (analysis of tissue). Only by knowing the location, size, shape, Gleason score and genomics (if necessary) can a customized treatment plan be made. We can, however, see how miR Sentinel has potential for ruling out a biopsy—though we believe it would be best to corroborate a negative miR Sentinel with 3TmpMRI. We also see the utility of using this urine test to monitor during Active Surveillance or follow-up after treatment. Ideally, mpMRI should still be integrated into a patient’s care plan.
This blog does not constitute an endorsement for miR Sentinel or any other particular biomarker-based test. We do, however, support the ongoing research and development of non-invasive tests to gain the earliest, most accurate indication that a man has PCa in order to determine next steps. If just peeing into a cup can help accomplish that, miR Sentinel may be the best mousetrap yet for capturing tumor information.
NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.
[i] Wei-Lin Winnie Wang W, Sorokin I, Aleksic I, Fisher H et al. Expression of Small Noncoding RNAs in Urinary
Exosomes Classifies Prostate Cancer into Indolent and Aggressive Disease. J Urol. 2020 Sep; 204(3):466-475.