When she teamed up with a neuroimmunology researcher at the University of Minnesota’s (UMN) Masonic Cancer Center (MCC) 20 years ago, veterinarian Liz Pluhar thought the two would spearhead a short-term project. The research would ask a simple but important question: How similar are the brain tumors that occur in dogs to those that show up in humans?

“What it turned into was a very successful brain tumor program,” Pluhar says.

Pluhar and John Ohlfest co-founded the Canine Brain Tumor Program in 2007, a unique collaboration between the UMN College of Veterinary Medicine (CVM) and the School of Medicine. Gliomas are aggressive brain tumors that occur in both humans and dogs at about the same rate. In both species, a glioma diagnosis carries a poor long-term prognosis. For nearly two decades, the Canine Brain Tumor Program has conducted clinical trials to investigate innovative treatments that could improve survival and quality of life for both dogs and people with gliomas.

“There are no other species that get these tumors as dogs and people do,” Pluhar says. “It gives us a really unique opportunity to take advantage of the fact that we have these canine patients, and that we can treat these dogs using many of the same methods used to treat people.”

An ideal model patient

Many initial studies on potential brain tumor therapies for humans have been conducted using rodent models. Because human tumor cells are placed in these rodents to test the effect a therapy has on the tumor, the models have to have inactivated immune systems.

“When they tried to transfer what worked in rodents to humans with brain cancer, less than 10 percent of those therapies worked in human patients,” Pluhar says. “It wasn’t a very relevant model.”

This is becoming ever more true as immunotherapies become the cutting-edge treatment for cancers. Dogs that have brain cancer are both in need of treatment and serve as the ideal model for human medicine—they have intact immune systems, as humans do, and very similar tumor cells.

Since its beginning, the Canine Brain Tumor Program has enrolled more than 350 dogs for treatment in clinical trials, which have been able to improve the quality and length of life in many of these patients. The canine patients in these trials first undergo surgery to remove as much of the brain tumor as possible, mimicking the first line of therapy for humans.

“That also allows us to get a definitive diagnosis, so we know what tumor every dog that we treated had. Other places that are doing clinical trials with dogs sometimes don’t even get a biopsy,” Pluhar says.

In a few cases, what was learned from the successes of these canine trials has paved the way for human clinical trials for people battling glioblastoma.

“There aren’t many places in the United States where there is a vet school and a medical school on the same campus. It made working together possible,” Pluhar says.

The next legacy

A few years ago, Pluhar began considering the future of the Canine Brain Tumor Program. She knew she was nearing retirement and made a call to someone she knew would be a natural fit to take over the program.

As a rotating intern with the CVM, Susan Arnold was laser-focused on pursuing a career as a clinical researcher and specializing in neuro-oncology.

"I cannot think of any other internship program in which a rotating intern could have had the opportunities that I had here at the CVM,” Arnold says. “I was scrubbing in with human neurosurgeons, getting to learn from them and Dr. Pluhar, and co-authored two papers with Dr. Pluhar that year."

Following her year-long rotating internship, Arnold completed a residency in veterinary neurology and neurosurgery at the University of Georgia College of Veterinary Medicine. One day, while she was wrapping up a busy day in the operating room, she received a call from Pluhar.

“I asked if she would be interested in coming back to the U. We would have several years of overlap, and then she would take over the program, and that’s exactly what happened,” Pluhar says.

Pluhar retired in July and has high hopes for the legacy of the Canine Brain Tumor Program to continue. Throughout the last two decades, the program has received funding from the National Institutes of Health and the American Brain Tumor Association, which has allowed the UMN to offer clinical trial patients therapy free of charge.

"Thanks to Dr. Pluhar's dedication, vision, and compassion, the program has a rock-solid foundation," Arnold says. "I am looking forward to broadening our collaborations, both with UMN partners and at other institutions."