The current standard test for prostate cancer is testing for concentrations of the biomarker prostate-specific antigen (PSA), in the blood. . The blood test is then complemented by biopsy which could determine the stage of the disease and whether the disease is slow-going or aggressive. Although blood testing and biopsies are standard procedures in diagnostic medicine in general, the methods are still rather invasive and pose risks for both patient and health care professional. Thus, the news of a simple urine test for prostate cancer is certainly welcome in the health care industry.
Researchers University of Michigan in Ann Arbor have identified a molecule in the urine that could reveal the state of disease in prostate cancer patients. The molecule has been identified as sarcosine
“a derivative of the amino acid glycine called sarcosine, after close inspection of all the metabolites found in 262 samples from prostate cancer patients – all of whom had different stages of the disease – including benign cells to aggressive metastasized cancers able to spread to other organs. Metabolites are the substances involved in or produced by the chemical reactions that take place in the body, and the concentrations of these chemicals can change as cancer progresses.” (Source: Nature News).
When tested in the lab, sarcosine induced normal prostate cells to behave like cancerous cells, indicating that the molecule is not only a biomarker, but also plays an active role in cancer development, making it a potential target for prostate cancer treatment.
The search for biomarkers for diseases has become the Holy Grail for biomedical researchers. While the search has proven to be easy in some diseases, it has proven to be difficult and complicated for others. Urine biomarkers have proven to be useful in urological, gynecological infections but not in cancer (until now). Urine as source of biomarker has the advantages of non-invasive collection method, an almost unlimited supply, can remain stable for long periods without special treatment or storage. However, studies have shown that protein content in urine can be low and variable while the high salt content seems to interfere with analytical methods.
According to Cancer Research UK, prostate cancer is the most common form of cancer in British men with about 35,000 new cases diagnosed each year in the UK alone. “The lifetime risk for being diagnosed with prostate cancer is 1 in 14.” In the US, 186,320 new cases were diagnosed and 28,660 deaths were reported in 2008 alone, according to the US National Cancer Institute.
The sarcosine test has the advantage of testing for prostate cancer as well as showing the stage of the disease and its aggressiveness without resorting to biopsy. It is currently being tried out in clinical trials is Europe.