Comparative Oncology: Trial cancer treatments for dogs could also lead to breakthroughs for humans
If you've ever lost a dog to disease, it may well have been cancer. Some 4 million dogs in the U.S. are diagnosed with it every year, often the same kinds of cancers as humans get.
We share many of the same genes with our canine companions. And, as we discovered last fall, for cancer research, that's an opportunity scientists are trying to make the most of. It's called comparative oncology. Now funded in part by the White House's Cancer Moonshot Initiative, doctors and scientists are studying naturally developing cancers, mostly in dogs, and using what they learn to speed potential treatments to them and us.
A dog show might seem like an odd place to conduct cancer research, but last summer in Norwalk, Connecticut, that's where we met scientists from the National Institutes of Health. Swabbing and collecting DNA samples from all sorts of breeds.
They've been doing this for nearly 30 years and have collected about 40,000 samples so far.
Leading the team is Elaine Ostrander, a senior geneticist at the NIH.
Anderson Cooper: I always thought that the National Institutes of Health studied human diseases. Why is there a scientist at the NIH studying dogs?
Elaine Ostrander: We are studying human disease, and we're doing it through dogs. And so dogs live in our world. They get all the same diseases we do. They eat our food. They're exposed to the same environmental pollutants. But they also have all the same genes that we do. And they have mutations in those genes that make them susceptible to everything you and I get - whether it's diabetes or cancer or neuromuscular diseases. Everything humans get, dogs get.
Ostrander says it's easier to study genes in dogs than humans because for the last 200 years, they've been bred to emphasize specific traits. That's why they have all these distinct noses and tails and sizes, from great danes to chihuahuas.
Anderson Cooper: So before Victorian times, dogs were pretty much the same?
Elaine Ostrander: So there was some variation. We know that from fossil and archaeologic records, but almost all the variation you see running around in-- in the rings today, that's all happened in the last 200 years.
Anderson Cooper: That's really incredible that there's so much variety in that short of time.
Elaine Ostrander: Right. So that means it's probably gonna be a really small number of genes responsible for most of the major differences.
It turns out just one gene determines if a dog has cream colored hair, or black. Other genes determine long hair or short. And Ostrander's team at the NIH has discovered some physical traits in dogs, like ear position, hold surprising clues about human health.
Elaine Ostrander: This was a study looking at prick ears versus floppy ears. And that's due to a mutation in-- in one gene called MSRB3.
Anderson Cooper: So just a mutation in one gene--
Elaine Ostrander: One gene. Isn't that amazing?
Anderson Cooper: --Makes the difference between pointy ears and--
Elaine Ostrander: Yep.
Anderson Cooper: --floppy ears.
Elaine Ostrander: Isn't that amazing? But what's really interesting about this story is that when this gene is perturbed or more dramatically mutated in humans, we get a form of deafness.
Anderson Cooper: Really?
Elaine Ostrander: Yeah.
Ostrander told us some of the most promising genetic research in dogs involves cancer.
Some breeds get certain types of cancers more often -- making it easier for researchers to locate some of the genes responsible. Scottish terriers, for instance, are about 20 times more likely to get bladder cancer than the average mixed breed dog.
Elaine Ostrander: Now, if I were to look at a group of humans with bladder cancer, the story would be so much more complex. There would be different genes in different populations. There'd be different mutations. Different contributions of environmental effects. So when I look in one breed, I get much simpler stories.
Dogs are diagnosed with many of the same cancers found in humans – lymphoma, melanoma, brain and breast cancer, and the deadly bone cancer osteosarcoma.
University of Pennsylvania professor and veterinarian Nicola Mason oversees a national network of comparative oncology trials funded by the White House's Cancer Moonshot Initiative. She showed us just how similar osteosarcoma looks in dogs and people.
Nicola Mason: So, what you can see, there's lots of purple dots here. These are the nuclei of the cancerous cells. They look identical.
Anderson Cooper: Yeah. Even a professional looking under a microscope would not be able to tell the difference between a dog with osteosarcoma and a human?
Nicola Mason: Correct. Incredibly similar.
Osteosarcoma is aggressive and malignant. More than 10,000 dogs in the United States are estimated to get it each year. But only about ,1000 people are, mostly children and young adults. Krystie Gomes was diagnosed in 2020, when she was 11.
Anderson Cooper: Which was the leg that was hurting?
Krystie Gomes: It's the left.
Anderson Cooper: So it was hurting up in your thigh.
Krystie Gomes: It was up in, like-- yeah, here.
Krystie was used to getting bruised on the soccer field, so she and her mom, Kathy Feder, chalked it up to a sports injury. But after months of physical therapy, her doctor discovered osteosarcoma had eroded most of Krystie's thigh bone.
Kathy Feder: She comes in and she goes, "Krystie has a cancerous tumor in her femur." And I was like, "What?"
Krystie Gomes: And I was-- I'm not, like, a crier. So I, like-- I think I was processing it. And as I was processing it, I saw her cry. So then I started crying.
Kathy Feder: And then she was like, "Wait. I have cancer?"
Doctors removed the remaining bone and replaced it with a 9-inch metal rod. Months of grueling chemotherapy withered Krystie to 72 pounds. But her pediatric oncologist, Dr. Elyssa Rubin, told us, the cancer came back - this time in Krystie's lungs.
Dr. Elyssa Rubin: Patients, once their tumor comes back, are at a really high risk, probably 80% of the time will get new tumors.
Anderson Cooper: Have there been a lot of new treatments for osteosarcoma?
Dr. Elyssa Rubin: Unfortunately, no. We've been using the same chemotherapy for about the last 60 years or so.
Anderson Cooper: Really?
Anderson Cooper: Is that because it's a rare form of cancer?
Dr. Elyssa Rubin: Yeah. It's harder to study 'cause there's smaller number of patients to, you know, study in large trials. And also since it's rare, not a lot of funding of-- goes to a lot of trials for it.
But there were trials in pet dogs of an experimental immunotherapy treatment for osteosarcoma that began in 2012, led by Dr. Nicola Mason, using the bacteria listeria.
Dr. Nicola Mason: This is listeria, causes food poisoning. This particular listeria has been genetically modified so that it is far less virulent.
The listeria has also been modified to contain a specific protein -- called HER2 -- that's found on some osteosarcoma cells. Once injected into the dogs' bloodstream, the listeria awakens their immune systems, making them feel sick. It also triggers killer immune cells to patrol the body and destroy the cancerous cells.
Sandy, a 9-year-old golden retriever, joined a nationwide trial in 2018. She's had her front leg amputated because of osteosarcoma. We met her this past August with her owner, Matt Olson. During the trial, Dr. Mason told us, Sandy's immune system reacted to the listeria just as she'd hoped.
Nicola Mason: Her body temperature started to increase, peaked around about four hours, and then started to drop down again. We sort of want to see that because it tells us that the immunotherapy is in fact stimulating her immune response, which is what we want to happen.
When Sandy was first diagnosed, her life expectancy with the standard care of amputation and chemotherapy, was around a year. But that was four years ago.
Anderson Cooper: There's no sign of cancer?
Nicola Mason: No.
Anderson Cooper: And you've had four great years with her?
Matt Olson: Yeah.
Anderson Cooper: Did she get, like, extra treats once she got through it all?
Matt Olson: She got everything. She still does man.
Anderson Cooper: She does? I bet she does.
Dr. Mason believes studying and treating naturally occurring cancers in pet dogs is more promising compared to using lab mice, which have to be artificially given cancer.
Nicola Mason: What we're trying to do is find a better way to determine which are the best treatments to take forward into the humans.
Anderson Cooper: This is not giving dogs rare forms of cancer and then studying them and testing them in a lab?
Nicola Mason: Exactly. So these are naturally occurring cancers. These are clinical trials, just as you or I would go onto a clinical trial if we had a cancer. And we do exactly the same in the veterinary field.
Results from the first listeria trial in pet dogs were encouraging -- showing the dogs "tolerated" the immunotherapy and that it "significantly increased duration of survival time." Those results were submitted to the Food and Drug Administration.
In 2021 the FDA approved a phase II clinical trial using modified listeria to treat young adults and children, like Krystie Gomes, who have recurrent osteosarcoma that's spread to their lungs.
We were with Krystie in August at Children's Hospital of Orange County when she received her third listeria infusion.
First, she was given medications that made her sleepy.
Anderson Cooper: When the infusion's actually happening, do you remember it afterward? Or, do you basically sleep through it?
Krystie Gomes: Just sleep. And then when I wake up, it hits like a truck.
Anderson Cooper: Is that right?
Krystie Gomes: Yeah.
Anderson Cooper: You get a headache?
Krystie Gomes: Uh-huh (AFFIRM). Bad headache and nauseous. And I hate nau-- nauseous and headache, two things I don't like. And it's two things guaranteed.
Once she was dozing, the listeria started dripping into Krystie's IV.
Anderson Cooper: It's kind of amazing to think that you're both on the cutting edge of medicine.
Kathy Feder: I know. And I don't think she, I don't think she realizes how important this is.
An hour later, that truck Krystie told us about hit her. Hard.
But similar to what happened to Sandy -- the golden retriever -- the listeria appeared to awaken Krystie's immune system. And after ten minutes her headache got better. A few hours later, she was able to leave the hospital.
Anderson Cooper: It's so amazing to me how similar humans' and dogs' immune response is.
Nicola Mason: We're very similar. You know, I think perhaps more so than we might like to admit.
The National Cancer Institute is spending more than $20 million to analyze cancer samples from pet dogs all over the country and oversee comparative oncology trials to improve treatments in humans and dogs.
One of their targets is brain cancer. This is Otto, a 7-year-old boxer who belongs to Dan Heffron. Otto was diagnosed with a deadly brain tumor in 2021.
And this is Julie Hinseth, who is 59, she was diagnosed in 2020 with a similar nearly incurable brain cancer - glioblastoma. She's had surgery, radiation, and chemotherapy, but the cancer came back. Julie and Otto enrolled in clinical trials at the University of Minnesota that used virtually the same experimental treatment.
A neurosurgeon and veterinary surgeon teamed up to treat and operate on Otto and other dogs with brain cancer and then shared their data about safety and dosing with a neuro-oncologist treating Julie and others.
Julie, along with her husband, Doug, and daughter, Kelly, met Otto for the first time last year. Two patients, similar cancers, different species.
Anderson Cooper: What's it like to meet Otto?
Julie Hinseth: Ah. I'm crying now.
Inflammation in Julie's brain makes it difficult for her to speak.
Anderson Cooper: I never thought I would be having a conversation with a person and and a dog who were having the same treatment.
Anderson Cooper: It's incredible.
Julie Hinseth: I didn't realize that until now.
Dan Heffron: Yeah, and I didn't until after his first surgery. You know, what sort of an impact that he was gonna have. You know, not only for him but other dogs and humans.
But two months after that meeting, Otto's symptoms worsened, it appeared his cancer returned. Dan took him for a final swim in his favorite river and then said goodbye to the dog he called his best friend and a medical pioneer.
Julie Hinseth's symptoms have now worsened as well, she's stopped taking part in the trial and has entered hospice care. She told us she is grateful to have been part of an innovative, inter-species battle to find new treatments.
Julie Hinseth: I helped fight cancer.
Anderson Cooper: It gives you satisfaction to know that you helped fight cancer.
Julie Hinseth: Yeah.
Anderson Cooper: I've had two dogs who have had cancer. And the idea that cancer can be studied and treated, and it can have an impact on humans, is incredible.
Julie Hinseth: Might be the key, right?
Anderson Cooper: Yeah, dogs may hold the key.
Krystie Gomes, who's now well into her freshman year in high school, says she agrees.
Krystie Gomes: We have to have more common things than we think.
Anderson Cooper: It's not just that they need us for food and that--
Krystie Gomes: It's not just that we're besties.
Anderson Cooper: there's really a connection.
Krystie Gomes: It's that we have to have, like, more connection than that.
Krystie's last scan showed no signs of cancer. She continues to get immunotherapy every three weeks. Between treatments and homework, you'll find her with her yorkie, Benny -- a gift from her mom. One more dog that's helping her in her recovery.
Produced by Denise Schrier Cetta. Associate producer, Katie Brennan. Broadcast associate, Annabelle Hanflig. Edited by Matthew Lev.
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