Sniffing Out Cancer

By Anastacia Mott Austin

We’ve heard from those who know that cancer stinks.

Turns out, it really does. Scientists this month have discovered in two separate studies that cancer molecules give off gases that are different from, well, the regular gases our bodies emit.

The studies were both inspired by dogs. The first study, performed by scientists at the Monell Chemical Senses Center in Philadelphia, and presented at the 236th meeting of the American Chemical Society, was developed after years of anecdotal reports of dogs being able to correctly identify melanomas based on their scents.

The researchers wanted to find out if gases, detectable as odors, were composed of different molecules than gases that are given off by healthy skin.

First the team examined healthy skin samples from 25 men and women. They determined that "regular" skin emits about 92 different molecular compounds into the air immediately around it, a combination of organically occurring molecules and those from soap and other environmental sources.

Then they narrowed down the chemicals to six naturally occurring gases, and when samples of skin with basal cell carcinoma (the most common form of skin cancer) were compared to the healthy skin, the chemicals were different.

What this means, say the researchers, is that the carcinoma cells have a different gas profile than regular cells, meaning they have a particular "odor" that could someday be used to help identify various types of skin or other cancers.

The second development in cancer detection research involves a team working at the University of Oklahoma. Led by electrical engineering and computer science professor Patrick McCann, the team hopes to develop a hand-held breath sensor that can detect cancer.

They’re using mid-infrared lasers to detect gases exhaled in human breath that may be markers of certain cancers.

The Oklahoma team’s research was also inspired by our canine friends. A study done in March of 2006 showed that dogs could accurately identify a high percentage of lung and breast cancers by sniffing samples of exhaled air from cancer patients (97 and 88 percent, respectively).

The researchers concluded that the dogs must be smelling chemical differences in the breath of cancer patients.

The Oklahoma researchers are not working, like the Monell team, to identify which gases are different, but rather they are developing the technology to enable doctors to do so with a high level of accuracy and ease of use.

Professor McCann says they plan to use nanotechnology to make the laser detection systems small enough to use as hand-held devices. Though the development of such a device could still take five to ten years before it would reach the public market, its potential significance to the field of cancer research and treatment is great.

"A device that measures cancer-specific gases in exhaled breath would change medical research as we know it," said McCann to reporters.

Just make sure to remember, when all is said and done, to thank your trusty pal Fido. The scientists involved in these studies, and future cancer patients, will be glad that cancer research has gone to the dogs.