Clemson professor looks to develop cancer screening test

CLEMSON, S.C. (AP) — When her younger brother was diagnosed with cancer, Clemson bioengineering professor Terri Bruce resolved to tap her knowledge of human cells to find a way to help others suffering from the disease.

View all (2)

After devouring all the scientific literature she could, she chose to focus on developing a screening test to detect the disease in its earliest stages when it has a better chance of being cured.

"It was a time in my life when I felt helpless," she told The Greenville News. "And I felt there's got to be something I can do — even if I can't help Greg — to help other people."

Because he suffered from brain cancer, she looked to another form of the disease that wasn't as emotionally entangled but had no early screening tests. She decided on ovarian cancer.

Now Bruce and her research team are on the brink of a test that they believe could be a screening tool — not only for ovarian cancer, but other cancers too.

"The hope," she said, "is to ... catch this deadly cancer much earlier and give women a fighting chance."

Ovarian cancer will strike 22,530 women this year, according to the American Cancer Society, and about 14,000 will die of the disease.

But only about one in five cases is discovered early because there are no reliable screening tests, the society reports.

A late diagnosis reduces survival. And because the symptoms are so vague, about three quarters of all women are diagnosed at a late stage, said Dr. Larry Puls, the director of gynecologic oncology at Prisma Health Cancer Institute.

Only 10% to 15% of them will survive long-term. And overall survival numbers haven't changed much in 40 years, he said.

Though blood work can test for a protein that can identify some ovarian cancers, only half of stage 1 patients test positive for it, Puls said.

"One of the things that has eluded us in ovarian cancer is that we have no screening for it," he said. "But if you can find it when it's confined to just the ovary alone, 90% of patients beat their cancer.

"If we could shift women out of stage 3 and into stage 1," he added, "we can make a huge impact on this disease."

For some time, Bruce has been studying exosomes, which are microscopic droplets found in body fluids that were traditionally regarded as a way for cells to rid themselves of debris.

But further research revealed that they contain parts of the cell they are from as well as proteins that can serve as biomarkers of what's going on in that cell, she said.

Cancer often develops because something goes awry in the DNA, leading to aberrant proteins and tumor growth, she said. So she theorized that finding those protein signatures in exosomes could be a way to diagnose cancer.

"If we can find those aberrant protein signatures and see them on the cells and exosomes," she said, " ... it potentially could be used for any type of cancer, as long as you find the biomarker."

The process has the potential to be used as a diagnostic tool for other diseases as well, she said.

So Bruce approached Clemson chemistry professor Ken Marcus, who'd been separating whole human cells for years using fiber strips, and asked if he could separate exosomes.

"I said, 'I don't even know what they are,' " he recalls with a chuckle.

"But she got us some samples and in pretty short order ... we made some really good educated guesses and it worked."

Marcus and his "very talented students" were not only able to separate the exosomes, but reduced the time needed to do it from 2 1/2 hours to 8 minutes using a test strip made of a polymer that is grooved much like the top of a zip lock bag.

When fluid is added, it flows down the channels where it interacts with different antibodies that in turn isolate the exosomes, he said, much the way a pregnancy test works.

Bruce and Marcus were then introduced to Puls, who joined the research team.

He's collecting samples of cervical fluid containing exosomes and proteins obtained at the same time as a pap test.

So far, 49 women have been tested with the strip, Puls said, and two who had no symptoms and normal blood tests were revealed to have stage 1 ovarian cancer.

"That's the patient we covet the most because we cure 90% of those patients," he said.

Puls also hopes the test will one day detect precancerous changes, enabling doctors to surgically remove the tissue — like they do when a pap test reveals a precancerous change — and prevent the development of cancer in the first place.

While the initial data will be crunched in the next few weeks, Puls said he's optimistic that the test could be a promising new tool in the battle against ovarian cancer.

He hopes the test could be used to screen for uterine cancer as well, which strikes another 63,000 women a year.

The Holy Grail for the process, Marcus said, would be a urine test because it can show what's going on inside the whole body. But the first step is testing cervical fluid in the doctor's office.

"And even that is an infinite step up from where we are today," he said.

Because tumors can be caused by a variety of proteins, the test will look for a bank of markers in an effort to capture more cancers, said Bruce, who is also director of Clemson's Light Imaging Facility.

"I think we're close on getting some kind of screening tool," she said. "And we're in the process now of (getting) all the patents."

So far, the research has been privately funded, but the team plans to use their initial data to apply for federal grants to continue their work.

They estimate a test could be ready for market in about five years.

Carmen Brotherton hopes the test will be routine in her daughter and grand-daughters' lifetimes.

The Easley woman's ovarian cancer was discovered in 2009, making her one of the few to be diagnosed in stage 1.

"I've lost some good friends ... who weren't caught in time," said Brotherton, who volunteers with the South Carolina Ovarian Cancer Foundation.

"It's always been one of my prayers that some day they would come up with something that would catch it," she said. "This is just a small place compared to the U.S. or the rest of the world. Imagine how many women this could catch. And it might save their lives."

When Bruce's brother was diagnosed in 2012, little could be done to stop the progress of the cancer, she said. He died in January, leaving his two sons fatherless.

Now she hopes the test will one day mean that fewer people will be left without a parent like her nephews.

"In conjunction with the discovery of distinct biomarkers, the fibers could lead to finding diseases such as ovarian cancer — and brain cancer — much earlier," she said.

"Early enough, I hope, to save many lives in the future."

___

Information from: The Greenville News, http://www.greenvillenews.com