Unusual means of detecting cancer early show great promise

Sniff and spit tests show promise
Tuesday, January 06, 2009
Angela Townsend
Plain Dealer Reporter

The start of a new year symbolizes beginnings, resolutions and, for researchers across the country, one step closer to finishing work that could change the way we fight cancer.

Although years away from hitting the market -- all must stand up to much larger studies and approval from the Food and Drug Administration -- the following tests show great promise in the quest for early detection of some of the most deadly cancers around.

The sniff test
Dr. Peter Mazzone imagines a day when patients suspected of having lung cancer will be able to skip having a biopsy -- an effective but risky procedure -- or a PET scan, an expensive imaging test. For several years, Mazzone, a pulmonologist with the Cleveland Clinic, has been working on perfecting his version of an "electronic nose."

Here's how the nose works: A person breathes into the machine for about five minutes, activating a small sensor. A miniature camera inside takes pictures of the sensor, which changes color. The camera sends the photos to a computer that is hooked up to the machine. The computer stores the images and analyzes the color changes for distinctive patterns.

Mazzone is now studying how the sensor picks up different compounds in a person's breath, whether or not a distinct color pattern occurs when compounds containing cancerous cells are present, and if the "nose" can sniff them out.

An earlier configuration of the "electronic nose" device was the size of a large copying machine that nearly filled a small office. On Dec. 1, Mazzone began using the newer, smaller version to test patients. He hopes to observe 1,000 patients before moving on to the next phase of the study.

Mazzone sees great potential in the nose, either to help identify people at high risk of developing lung cancer, or to catch the cancer early, in its most treatable form, before any noticeable symptoms appear.

"Everybody breathes anyway, so nobody seems to mind taking this," Mazzone said.

The blood test
Preliminary research led by Dr. David Cohn and Dr. Kimberly Resnick, gynecologic oncologists at Ohio State University, may pave the way for an effective new way to screen for ovarian cancer. Cohn and Resnick designed a blood test to find the presence of microRNAs, molecules that help regulate the proteins made by cells.

No one thought much of miRNAs being useful for anything. "In the basic sense, miRNAs were previously thought to be junk," Cohn said.

But that changed after Dr. Carlo M. Croce, director of human cancer genetics at OSU, did some breakthrough work on the subject. Cohn and Resnick used Croce's research to prove that it's possible to find microRNAs in the blood of women with ovarian cancer. Their blood looks much different from what is found in cancer-free women.

The findings are published in the journal Gynecologic Oncology.

Cohn and Resnick will continue their research this year by studying a larger population to get more significant results. They also have applied with Croce for a patent to develop the blood test.

If created, the test would be a huge improvement over the current CA-125 blood test, which is used mostly to detect recurrent ovarian cancer and is not always accurate.

The cure rate of women with ovarian cancer plunges drastically from 90 percent at stage one to 25 percent after that.

"Unfortunately, the symptoms are not easy to spot," Resnick said. They often include bloating, abdominal pain and frequent or urgent urination, symptoms so common that "everyone on this planet has at one time or another had them," she said.

The potential for a new blood test is enormous, Cohn said. "Whatever we can do to help decrease suffering is very exciting."