Researchers at the Mayo Clinic Florida campus may have stumbled onto an important bit of information when it comes to stopping the spread of prostate cancer.

They have identified an enzyme they believe causes prostate cancer to spread quickly to other parts of the body. Using this knowledge, they say they have developed a compound that reduces this molecule's ability to spread cancer cells.

“This molecule is a protease, which means it digests other molecules,” said the study’s senior investigator, Evette Radisky, a cancer biologist in the Mayo Clinic Cancer Center. “Our data suggests PRSS3 activity changes the environment around prostate cancer cells — perhaps by freeing them from surrounding tissue — to promote malignancy and invasiveness.”

Significant marker

Radisky says she doesn't think PRSS3 is the only factor involved in driving aggressive prostate cancer, but says it may be significant for a certain subset of this cancer, the kind that is potentially lethal.

Prostate cancer usually affects men over 50, developing in the prostate, which is a gland in the male reproductive system. Most prostate cancers grow slowly but the ones that are aggressive are usually the ones that prove fatal. That makes the Mayo Clinic findings all the more important.

By isolating the PRSS3 molecule in a patient's body, doctors may then know to look for cancer cells, or begin preventative treatments. In a test using laboratory mice, researchers found that cancer did not spread in animals in which the PRSS3 was neutralized.

'Jumped out at us'

“The link between PRSS3 activity and aggressive prostate cancer jumped out at us,” Radisky said. “We found a definitive trend of increasing PRSS3 expression with cancer progression.”

While prostate cancer remains a serious health concern for men over 60, the disease is becoming less threatening. American men with prostate cancer were 45 percent less likely to die from the disease in 2006 than they were in 1999, according to a 2010 report by the U.S. Agency for Healthcare Research and Quality.

The federal agency found that the rate at which American men died from prostate cancer declined from 23.5 deaths to 13 deaths per 100,000 males during the period. However, compared with white men, black men were still more than twice as likely to die from prostate cancer in 2006 just as they were in 1999, 69 to 50.5 deaths and 29 deaths to 22 deaths per 100,000 males during the period.

It's possible the Mayo findings will result in a new prostate cancer treatment – one that identifies and neutralizes the trouble-causing enzyme. Radisky says the drug researchers used in their trial does not have the characteristics of a “clinically useful” drug. However, she said it places researchers on the right path to develop one.


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