Urine Test Used to Diagnose Prostate Cancer

A novel enzymatic technique for the determination of sarcosine in urine samples could lead to a screening test for prostate cancer.

The concentration of the metabolite sarcosine can be determined by treating urine samples with a certain enzyme that interact with a substrate, which causes a chemical reaction that is measurable through different analytical techniques.

Scientists at the Missouri University of Science and Technology (Rolla, MO, USA) developed the technique by using the enzyme sarcosine oxidase on the urine samples to generate formaldehyde, which was further oxidized to formic acid. By observing these chemical reactions and examining the levels of fluorescence after the enzyme treatment, they were able to determine the amount of sarcosine in each of nine urine samples. The more fluorescence in each samples indicated a lower the level of sarcosine, while those with lesser fluorescence suggested a higher level of sarcosine.

Fluorescence emission spectra were obtained with a Fluorstar Omega microplate reader (BMG LABTECH; Ortenberg, Germany) equipped with a xenon lamp. Excitation and emission wavelengths were attuned to 485 nm and 520 nm, respectively. The technique could potentially be used to identify other metabolites associated with prostate cancer, but the findings greatest asset is its simplicity. Effective analysis and quantification of such metabolites in applicable media may then characterize the progression of certain cancers when practical difficulties would otherwise exist.

The scientists concluded that the low cost of their method compared with traditional prostate antigen (PSA) tests also presents a great advantage. They estimate that sarcosine test costs USD 0.1 per sample, compared with the approximately USD 70 it costs to get a PSA test at a health clinic or doctor's office. The article was published online in August 2012 in the journal Analytical Methods.

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Missouri University of Science and Technology
BMG LABTECH