Arnhem, 10 March 2009 — The standard Prostate Specific Antigen (PSA) test for prostate cancer cannot tell the difference between aggressive and slow-growing forms. At the Annual EAU Congress, which will be held from 17 to 21 March 2009 in Stockholm (SE), Dr. Arun Sreekumar – University of Michigan (US) – will report about a possible breakthrough biomarker that can supposedly discriminate between aggressive and non-aggressive prostate cancers: sarcosine.
“The PSA test,” explained Dr. Sreekumar to US media, “is the clinical standard test, but it has a very high false positive rate.” Sreekumar underlined that there is a danger to overtreat some patients or not to treat others. Quite often men have PSA scores that fall into a grey area. Then an invasive biopsy is needed to clarify a diagnosis. But even when a biopsy reveals cancer, it sometimes remains unclear whether the cancer is aggressive or indolent. Thus a biopsy does not always reveal who needs aggressive treatment.
Dr. Arun Sreekumar and his team of the University of Michigan measured the levels of chemical by-products, metabolites, of the reaction inside the human cells. Ten metabolites were found at much higher levels in prostate cancer than in normal samples and one of these metabolites stood out: sarcosine. Sarcosine can be identified in urine, which makes a possible test less invasive than PSA test, which requires a blood analysis.
The findings suggest that not only is sarcosine a marker of cancer aggressiveness, it also has a role in endowing a cancer with malignant properties. Sarcosine may distinguish slow-growing prostate cancers from those likely to spread and become lethal. On the other hand benign prostate cells take on cancerous characteristics in lab dishes when exposed to sarcosine.
“Metabolic profiles delineate potential role for sarcosine in prostate cancer progression” is the title of Sreekumar’s scientific article published in Nature recently (Nature, 457, 12 February 2009: 910-914). The research of Sreekumar and his team looked at more than 1,000 metabolites, or small molecules, in tissues associated with prostate cancer.
Dr. Arun Sreekumar, 37-year old lead author of the publication, recently started his new assistant professorship at the Medical College of Georgia Cancer Research Center. His work has been aiming at finding non-invasive ways to identify prostate cancer and predict its aggressiveness.