When it comes to the sense of smell, dogs far surpass the capacity of human beings. Humans sniff out odors using about 350 different olfactory receptors, but canines utilize more than 1,000 to inhale a world jam-packed with smells, including the volatile organic compounds or odorants altered in the earliest stages of ovarian cancer.
The ability to smell cancer is seldom used by doctors. But, combined with chemical and nanotechnology methods, Penn researchers hope to use dogs to develop a new system of early cancer screening that could save lives.
In an interdisciplinary project funded by an $80,000 grant from the Kaleidoscope of Hope Ovarian Cancer Foundation, the Penn Vet Working Dog Center, the Department of Physics and Astronomy in the School of Arts & Sciences, the Division of Gynecologic Oncology in the Perelman School of Medicine, and the Monell Chemical Senses Center are collaborating on a study that will take cues from the noses of dogs to isolate the signature odorant of early stage ovarian cancer.
“The idea behind the funded project is that, by combining information from dog studies, analytical chemistry, and nano sensor studies, we can make more rapid progress toward the goal of diagnosing ovarian and other cancers from their volatile signature,” says A. T. Charlie Johnson, a professor of physics and astronomy.
His team hopes to further develop its patented creation of a nanotube device to detect and identify odorants and other chemical compounds using single strands of DNA.
When a strand of DNA is attached to the carbon nanotube, it takes on a complex and specific shape, forming small, pocket-like structures that interact with molecules in the air.
“When we change the base sequence of the DNA, we get a device that responds differently to odors in the air,” Johnson says. “In a sense, we’re mimicking how we think your nose works. These devices can be extremely good at differentiating between very similar compounds.”
He says other potential applications of the nano sensor could monitor air and water for contaminants, or mimic service dog jobs such as tracking down people or drugs.
For this study, the Working Dog Center, Johnson’s group, and an analytical chemist at Monell will analyze tissue and blood samples from ovarian cancer patients. They will look for the chemical signature of the odorants from the patients, and check them against the volatile compounds emitted by healthy samples to confirm that they differ.
Together, the nano sensor, chemical analysis, and the noses of real dogs will help researchers refine their picture of the compound found in early stage ovarian cancer. Cynthia Otto, executive director of the Working Dog Center, says the dogs will act as biosensors that will help researchers identify the odorant signature.
Janos Tanyi, a Penn Medicine surgeon who is providing the blood and tissue samples and working on the medical side of the project, says the research could lead to novel methods to detect ovarian cancer.
Currently, doctors use expensive diagnostic tools to detect ovarian cancer, instruments that still fail to find the cancer until it has reached an advanced stage. Tanyi says more than 70 percent of ovarian cancer cases are diagnosed in Stage 3.
“If we could make a new screening method, it would be much easier to detect early stage cancer, and early stage treatment is much more effective,” he says.
Originally published on May 23, 2013