Details of a potential marker for prostate cancer discovered by researchers at Purdue University have been published in the journal Analytical Chemistry (2010;82:3430-34344).
Led by Graham Cooks, PhD, the Henry Bohn Hass Distinguished Professor of Chemistry, and Timothy Ratliff, PhD, the Robert Wallace Miller Director of the Purdue Center for Cancer Research, the team used a new analysis technique to create a profile of the lipids found in prostate tissue and discovered a molecular compound that appears to be useful in identifying cancerous and precancerous tissue.
The profile showed that cholesterol sulfate is absent in healthy prostate tissue, but is found in significant amounts in prostate cancer tumors.
“It was surprising to find a single compound that is distinctly present in cancerous tissue and not present in healthy tissue,” Dr. Cooks, who is also Co-director of Purdue's Center for Analytical Instrumentation Development, said in a news release.
“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. There was no single differentiator of which one could say that if it was present there was cancerous tissue.”
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, Dr. Ratliff noted.
The method used by the team to measure and compare the normal and cancerous prostate tissue is mass spectrometry desorption electrospray ionization (DESI). While conventional mass spectrometry requires chemical separations, the DESI technique eliminates this requirement by performing the ionization step in the air or directly on surfaces outside of the mass spectrometers, making the process much simpler, faster, and more applicable to medical examination or surgical settings, the researchers explained.
Dr. Cooks' team has also developed software that turns the distribution and intensity of selected ions within a sample into a computer-generated image that can precisely show the location of cancerous tissue and the borders of tumors. Livia Eberlin, a coauthor of the paper and a graduate student in the Cooks group, said the study showed promise in detecting precancerous lesions, as well.
“The DESI examination was able to distinguish a precancerous lesion in a small area of a sample made up of mostly healthy tissue,” Ms. Eberlin said. “By evaluating the difference in the chemistry of cells, this technique can detect differences in diseased tissue that are otherwise indistinguishable. It could provide a new tool for pathologists to complement microscopic examination.”
The team also plans to study differences in the chemistry of different types of prostate cancer tumors to see if there is a way to identify which are aggressive and which are not, she added.