Images from the desorption electrospray ionization mass spectrometry analysis of prostate tissue samples are shown next to stained slides of the same samples. The images show that cholesterol sulfate is present in cancerous tissue and precancerous legions called high grade prostatic intraepithelial neoplasia, or PIN. A Purdue University-led research team discovered that cholesterol sulfate is a potential marker for prostate cancer. (Photo courtesy of Demian Ifa/ Purdue Center for Analytical Instrumentation Development)
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Studies by a Purdue University-led team have revealed a potential marker for prostate cancer that could be the starting point for less invasive testing and improved diagnosis.

The team used a new analysis technique to create a profile of the lipids, or fats, found in prostate tissue and discovered a molecular compound that appears to be useful in identifying cancerous and precancerous tissue. The profile revealed that cholesterol sulfate is a compound that is absent in healthy prostate tissue, but is a major fat found in prostate cancer tumors.

Graham Cooks, professor of chemistry and Timothy Ratliff, director of the Purdue Center for Cancer Research led the team. “It was surprising to find a single compound that is distinctly present in cancerous tissue and not present in healthy tissue,” says Cooks, who is co-director of Purdue’s Center for Analytical Instrumentation Development. “We’ve been able to differentiate cancerous from healthy tissue using this new method in the past, but the difference was in the amounts of the same chemical compounds found in healthy tissue.”

Ratliff said this characteristic makes the compound a potential marker for the disease, which could lead to new blood or urine tests to screen for prostate cancer.

“Aside from skin cancer, prostate cancer is the most common cancer in men and is the second leading cause of cancer-related deaths,” Ratliff says. “Unfortunately, the current screening test has a significant number of false positives because it uses a marker that is present with other non-cancerous conditions. This new compound appears to be highly specific to prostate cancer cells, which would mean very few false positives.”

The current prostate cancer test screens for a protein called prostate-specific antigen, or PSA, that is produced by the cells of the prostate. Elevated levels of PSA in the blood can signify prostate cancer, but non-cancerous conditions such as an enlarged or inflamed prostate also cause an increase in its levels.

The findings of the study, which was funded by the Purdue University Center for Cancer Research and the National Institutes of Health, were published in the journal Analytical Chemistry. The study was performed in collaboration with physician scientists from Indiana University School of Medicine, who co-authored the paper. They also provided the tissue samples and pathological analysis of the samples to check the new technique’s results.

The team used a mass spectrometry analysis technique developed by Cooks and coworkers called desorption electrospray ionization, or DESI, to measure and compare the chemical characteristics of 68 samples of normal and cancerous prostate tissue.

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