Gursharan Kaur, wife of Prime Minister Manmohan Singh, at a walk for cancer patients in New Delhi on Sunday. Picture by Prem Singh

New Delhi, Feb. 15: Scientists have spotted a new chemical fingerprint of aggressive prostate cancer that may lead to better diagnosis and effective treatment strategies tailored for individual patients.

A research team in the US has identified a molecule named sarcosine in the urine of patients with prostate cancer that may be used to distinguish between benign, slow-growing, and aggressive prostate tumours.

“One of the biggest challenges in prostate cancer is determining if the cancer is aggressive. We end up over-treating patients because physicians don’t know which tumours will be slow-growing,” said Arul Chinnaiyan, professor of pathology at the University of Michigan and lead author of the study that revealed the sarcosine-cancer link. The study appeared in the journal Nature.

“We’ve identified a potential marker for aggressive tumours,” Chinnaiyan said.

The study suggests that sarcosine, a product of complex cellular activity, is a better indicator of aggressive, invasive and advancing cancer than the traditional prostate-specific antigen (PSA) used today.

Sarcosine could not be detected in samples of urine from men without cancer. But its level was elevated in 42 per cent of samples from early stage cancer, and in 79 per cent of samples from patients with advanced prostate cancer.

The researchers have shown that if an enzyme that is known to synthesise sarcosine is knocked off from prostate cancer cells through biochemical tricks, the invasiveness of the cancer cells weakens.

“The really powerful thing with this is that it gives us an insight into the biology of aggressive cancer and points to potential targets for new therapy,” said Christopher Beecher, a professor of pathology at the University of Michigan and team member.

“When we do something to reduce the concentration of sarcosine in the (prostate cancer) cell, it is no longer as aggressive. The cell appears to be using sarcosine to control its ability to move. Metastatic cancer cells have the ability to move,” Beecher told The Telegraph.

Urologists say the new advance may overcome some limitations of current diagnosis which is done through a digital rectal examination, a blood test that looks for PSA, and an ultrasound-guided biopsy.

“The PSA is the gold standard today. And we’re picking up prostate cancer through a combination of these three. But a test based on such a new approach would allow us to determine which patients need quick, aggressive therapy and which patients need only watchful waiting,” said Kim Mammen, national secretary of the Urological Society of India and urologist at the Christian Medical College, Ludhiana.

The 26-member team at the University of Michigan included at least eight researchers who had obtained their postgraduate, doctoral or medical degrees in India. The study’s first author, Arun Sreekumar, had studied at the Indian Institute of Science, Bangalore.

“These are early results that need to be validated. But a diagnostic test may be possible within three to five years,” Beecher said.

“Ultimately it could become a significant diagnostic tool for the diagnosis of cancer, not just for distinguishing between benign and aggressive prostate cancers,” he said.