Ohlin Frank, a chocolate lab whose focus has the intensity of Sherlock Holmes, is only on his fourth training session at Penn Vet Working Dog Center, but he has been able to detect ovarian cancer tissue 100 percent of the time.
He and his fellow trainee, McBaine Chamberlain, a spunky springer spaniel who is a bit more excitable, are part of an interdisciplinary research project at the University of Pennsylvania's to help scientists discover a chemical footprint that might lead to earlier diagnostic tests to save human lives.
They are among 15 carefully bred detection dogs learning to sniff out explosives, drugs and missing people. And now, they will use their keen sense of smell to identify the earliest odor of ovarian cancer, a silent killer that is often diagnosed too late.
Ovarian cancer will kill more than 14,000 women in the United States this year and 22,000 new cases will be diagnosed, according to the National Cancer Institute.
But doctors still don't have a good diagnostic tool for ovarian cancer, so they hope the dogs and their keen sense of smell can lead them toward one.
Cancer cells leave a detectable biomarker, just as asparagus can affect the smell of urine when eaten.
Within two years, Penn Vet founder and executive director Cynthia M. Otto hopes the dogs can be trained to narrow down a specific odor so scientists can design an inexpensive and less-invasive blood test to catch ovarian cancer while it's still treatable.
"All dogs are really good at sniffing, but part of what gives them a huge advantage over us is the surface area of the olfactory receptors," Otto told ABCNews.com as the dogs began their "search game" during a recent day's work at the lab.
After eight weeks of foundation training in obedience and agility, the dogs had already been introduced to the cancer tissue smell and were taught to sit when they found it.
"We had a party and played with them with toys," Otto said. "Then the game becomes, 'What do I have to do to get the toy?'"
"They get really excited and quickly figure out what they have to do to get their toys," she added.
Engineering students at Penn designed a large wheel with paint cans on the end of each spoke. Only one of the cans holds cancer tissue.
Ohlin's handler, Jonathan Ball, offered him a tug toy and praised the animal as the two roughhoused together. Soon, Ball tossed the toy to a second handler, Annemarie DeAngelo, who hid it in her shirt, then pretended to place the toy in each of the buckets.
DeAngelo swirled the wheel to mix up the empty cans with the cancer sample, as the handlers encouraged Ohlin, "Go get it, good boy."
And he did, every time, sitting patiently, awaiting his tug toy at the right bucket.
In previous research, dogs have been useful in detecting cancers of the breast, prostate, colorectal, bladder and skin. Penn Vet dogs Papa Bear, a chocolate Labrador retriever, and Bretagne, a golden retriever, are already helping alert diabetics when their sugar levels are too high or too low.
Otto, a veterinarian and researcher, founded the Penn Vet Working Dog Center in 2007 after spending 10 days right after 9/11 caring for the search-and-rescue dogs deployed in the burning rubble at the fallen World Trade Center.
"Originally, we went hoping for live humans," she said. "The rescue workers on the site did an incredible job of getting people out, but what was left were not survivors."
The terrorist attacks deeply affected Otto, and so now she is on a mission to use man's best friend to help humans.
"It's the intersection of how dogs help people," said Otto, the center's executive director. "It's a big place with lots of great aspirations, many of them already materializing."
The detection dogs -- both male and female, aged 8 to 11 months -- are each named for 9/11 dogs and their handlers and undergo twice-a-day training, five days a week.
The research is an interdisciplinary effort between the Penn Vet Working Dog Center and three arms of the University of Pennsylvania -- the physics department, the division of gynecologic oncology and the Monell Chemical Senses Center. It uses an $80,000 grant from Kaleidoscope of Hope Ovarian Cancer Foundation, but gets no funding from the university.
The grant funds three parallel studies: the biological one with dogs; an organic chemistry effort to create an artificial nose; and nanotechnology to develop a computerized screening instrument.
Otto's work builds on a 2010 Swedish study by Gyorgy Horvath, who used his own pet giant schnauzers to detect ovarian cancer. Tissue tests showed sensitivity of 100 percent and specificity of 95 percent; blood tests showed sensitivity of 100 percent and specificity of 98 percent.
Dogs with long noses -- hunting dogs like Labradors, golden retrievers and springer spaniels -- have the largest surface areas of olfactory receptors.
The first step is to get the dogs to recognize the odor in blood and then to move to a less-invasive test like urine or saliva. However, those types of samples won't have the same concentration of the odor, so it will be more challenging for the dogs and machines alike.
All dogs at the center are donated by breeders and go home each night to foster families. Some of the dogs will be part of the ovarian research and others, depending on their skills, will go on to military, law enforcement or service work.
Socks, Penn Vet's star golden lab, has just been assigned to the Pennsylvania Police Department to detect bombs.
"We look not only by breed, but how a dog is bred," said Otto. "They come from generations of hunting and working dogs selected for their ability to smell things."
According to one of the oncology collaborators, Dr. Janos L. Tanyi, a surgeon, cancer cells emit volatile organic compounds that have a distinct "signature" in the earliest stages of the disease, when cells are dividing.
"We believe that we can catch them when they are changing," he said.
Tanyi has asked 40 of his patients with the most common form of ovarian tumors to donate tissue from their surgeries. Most have advanced cancer.
"Between the surgery and the chemo, it's an exhausting and difficult time mentally and physically," he said of his patients. "They like it because it's fascinating and sounds like a bit of sunshine at a very cloudy time. They are really open for collaboration. ... They really want to help other patients."
Only about 10 to 15 percent of all ovarian cancer patients are diagnosed in the early stages when it is curable, because the symptoms are so "obscure," according to Tanyi.
Such was the case with Marta Drexler of Landsdowne, Pa., who had had a clean gynecologic exam just eight months before her diagnosis with advanced stage 3 ovarian cancer.
"This can happen, even if you are vigilant," said Drexler, 57.
She enthusiastically donated tissue samples from both her surgeries: "When Dr. Tanyi called, it was like the universe talking. ... It's a horrible disease."
Drexler worked for 20 years as a veterinary nurse and understands the powerful connection between humans and animals.
"I know their potential -- they are capable of so much," she said. "What I am excited about is all the women who will have a benefit from this in the future."
"Getting early detection -- that's what this is about," said Drexler. "It's a really simple idea. Dogs want to please us and do something for us."
Meanwhile, Otto said she feels an obligation to give back equally to her dogs. With a grant from the American Kennel Association, she has been able to continue monitoring the health of the 9/11 dogs for whom the research ones are named.
Unlike many of the humans who were exposed to toxins at Ground Zero, all six or seven of her surviving dogs, all retired, have remained healthy.
"Dogs are so important to our physical and mental well-being," said Otto. "Through my involvement with military working dogs and police and service dogs, there are so many aspects where dogs can make a difference for humans."
"I am surrounded by pictures of these dogs," she said. "I feel like it has opened some doors and I can make a difference in the world because of it."