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article courtasy of the Journal and Courier

For the past 10 years, Robert Wright has had a yearly screening for prostate cancer, "just to be sure everything is a-ok."

 

"If you catch it early, it's easier to correct than if you wait until it's a stage 3 or 4 status," said the 68-year-old West Lafayette man. "Plus, it's what the doctor tells me to do."

To screen for prostate cancer, physicians typically perform a digital rectal examination and a prostate-specific antigen test or PSA. But the PSA test can often yield false positives or negatives, making it an unreliable test on its own.

"Doing a blood test alone is not adequate screening for the disease because you are going to miss about 25 percent of the cancers," said Dr. Richard Selo, a urologist with Lafayette Clinic of Urology. "PSA is not a tumor marker, it's a screening tool, and you can have prostate cancer with a normal blood test."

Researchers at Purdue University are working on another test to add to the arsenal of prostate cancer screening tools. The test could be a potential marker for the cancer.

"The problem with prostate cancer is diagnostics at the moment are poor," said Graham Cooks, Purdue's Henry Bohn Hass Distinguished Professor of Chemistry. "PSA is quite well-known. That's a biomarker and is widely criticized because it often fails. What it doesn't really do is give an indication of the speed at which the disease will develop. So any alternative indicator would be very valuable."

The research team, led by Cooks and Timothy Ratliff, the Robert Wallace Miller Director of the Purdue Center for Cancer Research, found a molecular compound called cholesterol sulfate that appears to be useful in identifying cancerous and pre-cancerous tissue.

The researchers found that cholesterol sulfate is a compound found in prostate cancer tumors, but is absent in healthy prostate tissue.

However, more testing is needed to know if the presence of cholesterol sulfate in prostate tissues can serve as diagnostic tool.

"There is a long journey from discovering a molecule that might be a marker for a disease to having that molecule be looked for in a clinic on a routine basis..." Cooks said. " We've only taken the first steps in that journey."

However, he said the molecule they are looking at is easy to find and easy to analyze in blood and tissue and has the potential to be a useful marker for prostate cancer.

He said if it does become a marker for the cancer, it would look at a different aspect of the biochemistry and would add information to the PSA test.

Allison Dill, a Purdue doctoral student and part of the research team, said many men show some evidence of prostate cancer by the time they are deceased, but it might not be lethal or lessen their quality of life.

So while it's important to find out if men have prostate cancer early and treat it, it's also important to have more information about the disease such as if it's dangerous, progressing rapidly or what the best treatment options might be, she said.

"If we have the potential to provide different information in correlation with the PSA then it can help guide treatment options," Dill said.

article courtasy of the Journal and Courier - http://www.jconline.com/article/20100824/LIFE03/8240301