By Meghan Lepisto for VetMed.Wisc.edu
Could the body’s own immune system be primed to prevent cancer through a quick vaccine? A clinical trial launched this fall aims to bring new clarity to this complex question.
“We’re testing a totally novel way of creating an anticancer immune response,” said David Vail, a board-certified oncologist with UW Veterinary Care.
The Vaccination Against Canine Cancer Study will evaluate a vaccine strategy for the prevention, rather than the treatment, of cancer in dogs. With more than 800 patients enrolled as participants, it is the largest clinical trial conducted to date for canine cancer and across the history of veterinary medicine. The UW School of Veterinary Medicine is one of three participating institutions, together with Colorado State University and the University of California, Davis.
Cancer is the number one cause of illness and death in the aging dog population, with approximately one out of every three dogs affected and six million new cancer diagnoses made in dogs each year. If the trial is successful, it could not only provide a new strategy to prevent a critical health concern in canine companions, but it could also provide justification for studying a similar approach in people.
“The holy grail would be to prevent cancer, as opposed to waiting for it to start and then treating it,” said Vail.
Much like an influenza vaccine bolsters the body’s readiness to fight the flu, this preventative cancer vaccine follows the same principle—“to have the immune system primed such that if a cancer cell develops, it will attack,” Vail said.
Traditionally, vaccines work by introducing into the body a protein found on the surface of the virus that the vaccine is protecting against. The immune system sees the protein as a threat, establishes a memory of it, and then, if there is a later infection, recognizes that protein and is primed to react.
“It’s almost like putting up a wanted poster for that particular virus,” Vail explained. “When that virus infects you, then the immune cells recognize it because of the ‘poster,’ go out, and kill it.”
The anticancer vaccine now being tested targets approximately 30 abnormal proteins found on the surface of cancer cells. These proteins, a result of improperly coded RNA (so-called frame-shift mutations), are generally only found in patients with cancer (both dogs and people) and are agnostic of cancer type, meaning that a patient with breast cancer has the same abnormal proteins as a patient with bladder cancer. By injecting this cluster of proteins into healthy patients, along with a substance that stimulates an immune response, it’s theorized that the vaccine could serve as a universal defender against cancer by “turning on” the immune system.