How Dogs Are Helping Scientists Build A Smell Detector For Cancer

8:55 minutes

a german shepherd walks around a metal apparatus smelling the different ends of prongs
Read and watch the story on Methods, from Science Friday Credit: Luke Groskin

You’ve probably heard of dogs sniffing out drugs and bombs. But scientists are now training dogs to sniff out cancer. A team at UPenn and Monell Chemical Chemical Senses Center are using dogs’ heightened sense of smell to detect the specific chemicals produced by cancer cells. The scientists are using this data to produce a device that could be used in ovarian cancer detection. 

Science Friday’s video producer Luke Groskin and digital producer Daniel Peterschmidt talk with Ira about a trip to the cancer laboratory, where they met the scientists—and dogs—behind this unique research. This is part of Science Friday’s Methods, where we bring you into the field alongside the scientists working to answer big questions, by using gorgeous video and pictures. You can read the article and watch the videos about their trip at sciencefriday.com/smellingcancer

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Segment Guests

Luke Groskin

Luke Groskin is Science Friday’s video producer. He’s on a mission to make you love spiders and other odd creatures.

D. Peterschmidt

D. Peterschmidt is a producer, host of the podcast Universe of Art, and composes music for Science Friday’s podcasts. Their D&D character is a clumsy bard named Chip Chap Chopman.

Segment Transcript

IRA FLATOW: Dogs have aided people for centuries. Search and rescue dogs save human lives in disasters, and they are certainly helping many of us stay calm at home. Of course, there are bomb-sniffing dogs and drug-sniffing dogs. And now there is a cancer-sniffing dog. Yeah? Dogs can sniff and detect deadly hidden ovarian cancer.

A team at UPenn and Monell Chemical Senses Center is using data from dogs to build a device to make previously undetectable cancers a thing of the past. SciFri video Producer Luke Groskin and digital producer Daniel Peterschmidt visited this dog research lab, and they tell the tale in our methods project, which using video and pictures, brings you into the field alongside the people working to answer big questions. You can watch the videos and read about their trip at sciencefriday.com/smellingcancer. And now they’re here with us. Hi, Luke and Daniel,


DANIEL PETERSCHMIDT: Hey, Ira. How’s it going?

IRA FLATOW: Pretty good. Let’s talk about it. This research takes place in a few labs. What does the dog lab look like?

LUKE GROSKIN: Well, it doesn’t exactly look like a lab. It’s certainly not the dog type of lab, no pun intended. But it looks a little bit more like a kennel than anything else. You have a whole bunch of dogs that have very well-tended cages as well as a workout room and several rooms where they can sniff out different sort of chemicals or substances. And then there’s, of course, you know, an obstacle course, a rubble pit where they can go digging and looking for hidden things for the rescue dogs.

IRA FLATOW: Mm-hmm. I’ve heard stories, all kinds of stories, about dogs being able to detect epileptic seizures or panic attacks and alerting their owners. How did these researchers know that the dogs would be able to pick up the cancer?

DANIEL PETERSCHMIDT: Yeah, the head of the Penn Working Dog Center, Dr. Cynthia Otto, she told us that she always suspected dogs could do this type of work. You know, as you were just saying, you’ve probably heard stories of people whose dogs who would keep whining at them or continually nudging their stomach, or something, as if there was something wrong. And then they would get it checked out, and a tumor would end up being there. And then all these research papers kept popping up that different cancers had specific odors, and dogs are amazing smellers. So Otto had a pretty good hunch that they could be taught how to smell ovarian cancer.

IRA FLATOW: So could my daughter’s pug smell cancer?

LUKE GROSKIN: Technically, biologically, yes. The structure of its nose and its brain is able to pick up on all the vivid colors and smells of the world, as it were. But in terms of its training, probably not. Most dogs aren’t trained the way that these dogs are trained. These dogs, Ira, are incredibly well trained. They are elite, Olympian-class dogs. [IRA CHUCKLES] They are bred and raised from being puppies just for these sorts of tasks.

So the Working Dog group at Penn Vet– this is all they do. They work with their dogs day in, day out. They have these huge blackboards all over the place that show what the dogs’ schedules looks like. And they are kept to a very rigorous schedule. So could your daughter’s pug do it? Probably not. They probably couldn’t tell you that there’s cancer there, although they probably could actually smell it. They wouldn’t know what it is.

IRA FLATOW: Yeah, yeah. Well, speaking of what it is, that’s my next question. What exactly does a dog detect when they’re smelling cancer?

LUKE GROSKIN: Oh, that’s a great question. So when you think of what’s going on inside your body and what gets kind of exuded out of your body in the form of smell, it’s a very rich tapestry, especially in the nose of a dog. So the cancer cells, if you had cancer inside your body, would be producing all sorts of chemicals just like any other cell in your body would be producing chemicals.

The only difference is that in cancer, they’re producing a specific amount of those chemicals. And they’re getting released into your bloodstream, and then eventually some of them are you going to get released out of your body through either your urine or your sweat. And in this case, the dogs actually aren’t smelling people. They’re actually smelling blood plasma samples from cancer patients, and these are all collected from patients at a hospital. Some have benign growths. Some have more malignant growths.

And they also take samples, you know, a control sample where the people are healthy. They place those samples in jars around what looks like the little spokes that come out of a wheel, and they put them in these little containers. And the dog goes into this room, and it walks around this wheel sniffing at each of the different samples. And when it spots one that it thinks it believes has the cancer sample, it puts its nose right up against it and stays there. And just kind of focuses heavily on that sample.

It gets a little bridge click, [CLICKS] and then it comes back, and it gets a little reward if it got the right answer. And once the animals are trained to identify the specific cancer, they can do this very quickly. I mean, we watched them, and they do it like [SNAPS] that. It’s very quick. They go around, and they immediately can spot these sorts of cancer samples.

IRA FLATOW: Wow. I’m Ira Flatow, and this is Science Friday from WNYC Studios. But the point is not to have to create a whole bunch of dogs, service dogs, that would go into doctor’s offices and sniff patients.


IRA FLATOW: That’s not what they’re doing here.

LUKE GROSKIN: No, these dogs are never– I mean, they made a very explicit point about this. These dogs are never going to see a patient. That is not a very reliable way to diagnose somebody, because the patient could be cueing them. The doctor could be cueing them. These dogs don’t get any cues when they do these tests.

So they have no intention of bringing the dogs into a clinical setting. They’re a diagnostic tools. They are the gold standard of cancer detection. They are far better than any sort of equipment. There’s another lab that’s working with them– Monell Chemical Senses Center. And what they do is they’re trying to isolate the specific odors that the dogs are picking up that represent cancer.

Is it all of the different chemicals from the blood sample that represents cancer when there’s cancer in there? Or are there very specific odors in there? And then what they can then can do is they can build a sensor equipment, a apparatus, a device that actually can detect those specific chemicals in the very specific quantities for different types of samples.

IRA FLATOW: The team is starting with ovarian cancer. Why start with this type of cancer?

DANIEL PETERSCHMIDT: Yeah, yeah. So the oncologist on this research, Dr. Janos Tanyi– he called ovarian cancer a mean, mean disease. It’s the fifth most deadly cancer in women. It has close to 14,000 deaths per year. And partly why that is is that it has no noticeable symptoms until it gets to stage three or four. And at that point, the chemotherapy doesn’t have a lot of effect.

And those symptoms are just incredibly normal. It’s like a little bit of bloating or discomfort, which happens to everybody. And even if you suspect you have something up and you go to the doctor, often, they can’t find anything that’s wrong. So there’s no way to detect it early. And that’s why the team is building this device. They know ovarian cancer has a smell.

They’re pretty sure the dogs can smell it at early stages. And if dogs can smell it, as one of the researchers put it, they can definitely smell it through instrumentation if there’s something chemical going on. And hopefully what they learn from making this device is that they can build these odor profiles for other hidden cancers and apply the same methodology to them.

IRA FLATOW: Hm. Daniel, you and Luke visited these smell research labs?

DANIEL PETERSCHMIDT: Yeah, yeah. So we traveled down to Philadelphia last year. We interviewed and filmed these researchers in their labs. And from that trip and some other reporting, we put together a documentary video and a long-form article that takes a deep dive into the people and the dogs behind the project. And in that article, we have those videos sprinkled throughout it. And, you know, there’s dogs in it. [LAUGHTER]

IRA FLATOW: Well, I got a sneak preview of it. I started reading the article. It’s terrific. You can see the piece, watch the videos, if you want to do that. Both of those at sciencefriday.com/smellingcancer. Thank you, guys. Thanks, Luke. Thanks, Daniel.

LUKE GROSKIN: Thank you, too.


IRA FLATOW: You’re welcome. SciFri video Producer Luke Groskin and digital producer Daniel Peterschmidt.

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Alexa Lim was a senior producer for Science Friday. Her favorite stories involve space, sound, and strange animal discoveries.

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Ira Flatow is the host and executive producer of Science FridayHis green thumb has revived many an office plant at death’s door.

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