As the search continues for the perfect noninvasive diagnostic test for prostate cancer (PCa), investigators are exploring various ways to analyze urine. I want to describe three unique methods that are currently being tested.
According to a Johns Hopkins article, dogs may have a new way to be man’s best friend. They can detect PCa by smelling urine samples! According to a 2021 published paper, the ability of a dog’s nose “… far exceeds that of humans … allowing them to not only gather both current and historical information about their surrounding environment, but also to find the source of the smell… Dogs can be trained by humans to use their olfactory abilities in a variety of fields, with a detection limit often much lower than that of sophisticated laboratory instruments.”[i] In the case of medically trained dogs, what exactly are they smelling? One theory says that the presence of cancer alters bacteria in the urinary tract, changing the odor of pee. Researchers are working to pinpoint exactly which molecules a dog’s sniffer is picking up, in hopes of eventually developing “electronic noses” that can identify airborne molecules.
Of course, the practicality of keeping and training dogs poses challenges of cost (upkeep, personnel) and training time. Believe it or not, insects like ants offer a cheaper and more efficient detection system. Ants have highly developed chemosense and use chemicals to communicate with each other. They have an extremely accurate sense of smell, which helps them find food in two ways: 1) they find sugars and other ingredients by scent, and 2) as they travel, they deposit a chemical trail of substances called pheromones, allowing other ants to smell the trail leading to the source of food. Cancer cells emit specific molecules called volatile organic compounds (VOCs). One species of worker ants were shown to “… quickly learn to associate an olfactory stimulus with a food reward and retain this information for an extensive period of time (several days).”[ii] By rewarding ants with a sugar solution, they were quickly trained to detect PCa VOCs in human pee. Now, I’m not suggesting that ants make good trainable pets—you might be inviting an infestation in your kitchen—but they do offer the potential to make decent diagnosticians.
If you prefer a diagnostic pee test that does not depend on canines or creepy-crawlies, you might find it easier to simply dip a piece of specially treated paper strip into a urine specimen. You then scan the strip with a handheld biosensor that integrates spectroscopy with Deep Learning (a form of Artificial Intelligence). Spectroscopy is an accurate method of reading a biochemical signature. This is like identifying a fingerprint of cancer cells. A study of this method was most recently reported to have successfully classified both prostate and pancreatic cancers.[iii]
There are numerous ongoing trials of ways to pick up PCa from a urine sample. This has obvious advantages over the PSA test, which involves a blood draw and is not specific for cancer. Developers are working on an at-home PCa urine test. While we’re not quite there yet, I suspect the day is not too far off when diagnosing PCa is as simple as peeing in a cup.
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] Kokoci?ska-Kusiak A, Woszczy?o M, Zybala M, Maciocha J et al. Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Applications. Animals (Basel). 2021 Aug 1;11(8):2463.
[ii] Piqueret B, Bourachot B, Leroy C, Devienne P et al. Ants detect cancer cells through volatile organic compounds. iScience. 2022 Feb 22;25(3):103959.
[iii] Linh VTN, Lee MY, Mun J, Kim Y et al. 3D plasmonic coral nanoarchitecture paper for label-free human urine sensing and deep learning-assisted cancer screening. Biosens Bioelectron. 2023 Mar 15;224:115076.