New approach to prostate cancer detection - Sarcosine may distinguish between slow-growing and aggressive prostate cancers

On Friday 20 March, US researcher Dr. Chris Beecher from the University of Michigan gave a well attended lecture about sarcosine, an N-methyl derivative of the amino acid glycine, at the 24th Annual EAU Congress in Stockholm, Sweden.

Dr Beecher is a colleague of lead author Dr. Arun Sreekumar. The research of Sreekumar, Beecher and their team looked at more than 1,000 small molecules in tissues associated with prostate cancer. These findings suggest that not only is sarcosine a marker of cancer aggressiveness, it also has a role in endowing a cancer with malignant properties.

Sreekumar's publication in 'Nature' (457, 12 February 2009: 910-914) has attracted a lot of scientific and also popular attention. The EAU Scientific Congress Office inserted a special breaking news session in the congress programme in order to present the most updated scientific information in Stockholm.

Sarcosine may distinguish slow-growing prostate cancers from those likely to spread and become lethal. Conveniently, sarcosine can be identified in urine, a less invasive test than the blood analysis needed for the standard prostate-specific antigen (PSA), a protein produced by the cells of the prostate gland. PSA is present in small quantities in the serum of healthy men, and is often elevated in the presence of prostate cancer. Quite often men have PSA scores that fall into a grey area. Therefore, invasive biopsy is needed to clarify a diagnosis.

But even when a biopsy reveals cancer, it often remains unclear whether the cancer is aggressive and at risk of spreading, or indolent and likely to stay put. Rather than looking for genes or proteins, Dr. Arun Sreekumar and his team of the University of Michigan measured the levels of chemical by-products of the reaction inside the human cells. These chemicals are called metabolites. They looked into 42 tissue samples, 110 blood samples and the same number of urine samples from patients with advanced prostate cancer, early prostate cancer and men with benign disease. Ten of these chemicals were found at much higher levels in prostate cancer than normal samples. One of these metabolites stood out: sarcosine.

According to Dr. Beecher, the results are promising: "Sarcosine continues to predict the aggressiveness of the tumours". The metabolomic analysis yielded the observation that sarcosine was highly associated with tumour development. The scientific data support a correlation and provide biological insights.