Man’s best friend can also help us fight cancer.
Some 4 million dogs in the United States are diagnosed with cancer each year, often of the same type as humans. And because we share many of the same genes with our canine companions, dogs with naturally occurring cancers are enrolled in clinical trials, with doctors and scientists using what they learn to speed up potential treatments for them and for us. . It’s called comparative oncology, and it’s now funded in part by the White House’s Cancer Moonshot Initiative.
This week on 60 minutes, correspondent Anderson Cooper met National Institutes of Health scientists while collecting DNA samples at a dog show in Connecticut. The team was led by Elaine Ostrander, a senior geneticist at the NIH.
“Dogs live in our world. They get the same diseases that we do. They eat our food. They are exposed to the same environmental pollutants,” Ostrander told Cooper. “But they also have all the same genes that we do. And they have mutations in those genes that make them susceptible to whatever you and I get – whether it’s diabetes, cancer or neuromuscular diseases. Whatever the humans catch it, dogs catch it.”
Ostrander said it is easier to study genes in dogs than in humans because over the past 200 years they have been bred to emphasize specific traits such as noses, tails and different sizes.
“So before Victorian times,” Cooper asked Ostrander, “dogs were pretty much the same?”
“There were some variations,” Ostrander said. “We know this from the fossil and archaeological record, but almost all of the variation that you see running in – in the rings today, all of that happened within the last 200 years.”
“So that means it’s likely to be a very small number of genes responsible for most of the major differences,” Ostrander continued.
It turns out that a single gene determines whether a dog has cream or black colored hair. Other genes determine long or short hair. And Ostrander’s team at the NIH found that certain physical traits in dogs, like ear position, hold surprising clues about human health.
“This was a study looking at erect ears versus droopy ears. And that’s due to a mutation in — in a gene called MSRB3,” Ostrander said. “But what’s really interesting about this story is that when this gene is disrupted or more radically mutated in humans, we get a form of deafness.”
Ostrander said 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 pinpoint some of the causative genes. Scottish terriers, for example, are about 20 times more likely to get bladder cancer than the average mixed-breed dog.
“If I were to look at a group of humans with bladder cancer, the story would be so much more complex,” Ostrander said. “There would be different genes in different populations. There would be different mutations. Different contributions from environmental effects. So when I look into a race, I get much simpler stories.”
Dogs are diagnosed with many of the same cancers found in humans – lymphoma, melanoma, brain cancer, breast cancer and the deadly bone cancer osteosarcoma.
Osteosarcoma is aggressive and malignant. It is estimated that more than 10,000 dogs in the United States are affected each year, but only about 1,000 people, mostly children and young adults.
Krystie Gomes was diagnosed in 2020 when she was 11 years old.
Krystie used to get bruised on the soccer field, so she and her mom, Kathy Feder, blamed it on a sports injury. But after months of physiotherapy, her doctor discovered that osteosarcoma had eroded most of Krystie’s thigh bone.
Doctors removed the remaining bone and replaced it with a 9-inch metal rod. Months of grueling chemotherapy withered Krystie to 72 pounds. Then, said her pediatric oncologist, Dr. Elyssa Rubin, the cancer came back — this time in Krystie’s lungs.
“Patients, once their tumor comes back, are at very high risk, probably 80% of the time will have new tumors,” Rubin said.
“Have there been many new treatments for osteosarcoma? Cooper asked.
“Unfortunately, no,” Rubin said. “We’ve been using the same chemotherapy for about 60 years.”
“Is it because it’s a rare form of cancer? Cooper asked.
“Yeah. It’s harder to study because there are fewer patients to, you know, study in large trials,” Rubin said. “And also because it’s rare, not a lot of funding goes to a lot of trials for that.”
But there have been trials in pet dogs of an experimental immunotherapy treatment for osteosarcoma that began in 2012, led by University of Pennsylvania professor and veterinarian Dr Nicola Mason.
“It’s listeria, which causes food poisoning,” Mason said. “This particular listeria has been genetically engineered to be much less virulent.”
The listeria had also been modified to contain a specific protein – called HER2 – found on some osteosarcoma cells. Once injected into the bloodstream of dogs, listeria woke up their immune systems, making them sick. It also triggered killer immune cells to patrol the body and destroy cancer cells.
Sandy, a 9-year-old golden retriever, participated in a national trial in 2018. She had her front leg amputated due to osteosarcoma. During the trial, Dr. Mason said, Sandy’s immune system reacted to the listeria as she had hoped.
“His body temperature started to rise, peaked around four hours, then started to come down again,” Dr Mason said. “We kind of want to see that because it tells us that the immunotherapy is actually boosting his immune response, which is what we want to happen.”
When Sandy was first diagnosed, her life expectancy with standard amputation and chemotherapy care was around a year. But that was four years ago and Dr Mason said there were no signs of cancer.
Other results from the first listeria trial in companion dogs were also encouraging, showing that dogs “tolerated” immunotherapy and that it “significantly increased survival time”. These results have been submitted to the Food and Drug Administration.
Last year, 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 has spread to their lungs.
In August, Krystie received her third listeria infusion.
“When the infusion actually takes place,” Cooper asked him, “do you remember that after the fact? Or are you basically sleeping through it all?”
“Just sleep. And then when I wake up, it hits like a truck,” Krystie said. “Bad headache and nausea. And I hate nausea and headaches, two things I don’t like. And that’s two things guaranteed.”
First, Krystie was given medication that made her sleepy. Once she was dozed off, the listeria started flowing through her IV. An hour later, the truck Krystie was talking about hit her. Hard. But like what happened to Sandy, the golden retriever, the listeria seemed to wake up Krystie’s immune system.
After ten minutes, his headache got better. A few hours later, she was able to leave the hospital.
The National Cancer Institute spends more than $20 million to analyze cancer samples from pet dogs across the country and oversee comparative oncology trials to improve treatments in humans and dogs.
Krystie, who is now well into her freshman year in high school, had no signs of cancer at her last ultrasound. She continues to receive immunotherapy every three weeks. Between care and homework, you will find her with her yorkie, Benny, a gift from her mother, Kathy Feder. Another dog to help her in her recovery.
“It’s pretty amazing to think that you’re both on the cutting edge of medicine,” Cooper told Feder.
“I know,” Feder said. “And I don’t think she realizes how important that is.”
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