BAR HARBOR, Maine — In order to better understand and treat cancer, researchers often turn to experimental models that allow thorough observation and experimentation without the involvement of actual human patients. Common examples of these practices include cancer cells placed in a dish to more complex strategies like tumors being transplanted into lab mice for observation. Unfortunately, this approach isn’t efficient in all types of cancers, due to the fact that it is impossible for researchers to recreate the exact conditions of the human body within an external environment.
Now, a new study conducted at Jackson Laboratory may have found a novel way to study and analyze one of the historically hardest to treat forms of cancer in humans: Diffuse glioma, or the most common form of brain tumor. Researchers say studying and treating brain tumors in dogs will lead to effective treatment options for humans, especially children.
Brain tumors appear in domesticated dogs about as often as in humans, and just like among people, they are notoriously difficult to treat. On that note, caring for a dog suffering from a brain tumor can be very difficult for his or her family. With this in mind the research team say that dogs in this situation may benefit from experimental tumor treatments.
However, it wasn’t previously known how similar dog brain tumors are to human brain tumors. So to start, the study’s authors gathered 83 posthumous dog tumor samples for molecular examination. Then, they compared the results of their analysis to brain tumor information collected from both child and adult brain tumor patients. Indeed, they noted quite a few striking similarities between dog brain tumors and tumors seen in human adults as well as children.
These similarities included mutations in certain genes and pathways, including the DNA repair system that is always changed in human brain tumors. Similar fluctuations in the number of chromosomes were also observed. Most notably, brain tumors seen in dogs are especially similar to tumors seen in human children, even more so than adult brain tumors.
The study’s authors also examined how closely canines’ immune responses to brain tumors mimicked that of humans. Again, it was observed that dogs’ immunological response to a spontaneous brain tumor closely resembled what happens in human bodies.
This is especially helpful because, while immunotherapies in human medicine have shown great promise in cancer treatment, it’s been difficult to achieve high patient response rates. Incorporating immunotherapies into dog treatments may be an innovative and effective way to measure their overall effectiveness in both dogs and people.
All of the similarities between human and canine brain tumors point to these cancers “adapting” to the same environmental pressures experienced by both species. Of course, a dog’s lifespan is much shorter than a human’s, with the old adage stating that one human year of aging represents the equivalent of seven dog years. As such, the dog tumor samples used in this study didn’t show as many mutations as tumors examined from human adults. Instead, the dog tumors much more closely resembled adolescent human brain tumors. This aspect of canine brain tumors may prove useful in studying the role of age when it comes to fighting tumors.
All in all, the research team believe their findings indicate that if a cure for canine brain tumors can be developed, it would in all likelihood be very effective against brain tumors seen in human children as well.
The study is published in Cancer Cell.