Urinary biomarkers expand possibilities for prostate cancer detection

Simpa Salami, MD, MPH

Urology Times® is celebrating its 50th anniversary in 2022. To mark the occasion, we are highlighting 50 of the top innovations and developments that have transformed the field of urology over the past 50 years. In this installment, Simpa Salami, MD, MPH, discusses the development of urinary biomarkers in prostate cancer detection. Salami is an assistant professor of urology at the University of Michigan, Ann Arbor.

Could you give an overview of the development of urinary and molecular detection of prostate cancer?

One of the challenges in prostate cancer diagnosis is the heterogeneous and multifocal nature of the disease such that tissue-based biomarkers are not robust when it comes to picking up aggressive prostate cancer in patients with apparent low grade disease. Urinary biomarkers have created an avenue of overcoming those limitations. One of the earlier urinary biomarkers that was introduced into clinical practice was PCA3. This is a noncoding RNA that is expressed in urine that was shown to be predictive of prostate cancer in men who are undergoing repeat biopsy. Since then, there have been a number of biomarkers or a combination of biomarkers that have been developed. Currently, we have SelectMDx; we have ExoDx; we have the Michigan Prostate Score, or My Prostate Score Urine test; and PCA3, of course, that are used routinely in the diagnosis of prostate cancer.

Why should urinary markers be included in a list of innovations in urology?

The application of molecular tools to aid prostate cancer diagnosis was initially evaluated in biopsy tissue that is obtained from patients who are at risk of prostate cancer or tissue that is acquired at the time of radical prostatectomy. But what we have found is that the molecular profile in any given tissue may be different within the same region of cancer, or within different areas of the prostate. However, it's quite possible that a urine assay or a liquid biopsy approach may be able to capture what is going on in the entire prostate. So I think it is really an innovative approach to be able to translate what we have learned in prostate cancer tissue to urine to see if we can pick up aggressive prostate cancer in urine.

Do you predict any future innovations in urinary biomarkers for prostate cancer over the next several years?

Absolutely! Our ability to develop innovative technologies and approaches continues to evolve. We have newer molecular profiling techniques that are being applied to urine at the moment. The tests that I mentioned previously are either 1 or 2 or 3 biomarkers that are included in the development of this algorithm. We now have the capability of developing a next-generation sequencing assay in urine, so the ability to pick up not just 1 or 2 or 3 transcripts in urine, but numerous amounts of transcripts. I see a future where we'll be able to develop a test that will really be able to capture what is going on in the majority of patients. We may not be able to capture what is going on in every patient, but by expanding the molecules or the assays that these tests can pick up, we may be able to help overcome the issues that we encounter when it comes to diagnosing prostate cancer.