The Future of Vaccines to Prevent Canine Cancer

Beagle getting a vaccine by a veterinarian
Dogs are quite susceptible to cancer. In fact, one in four dogs will be diagnosed with cancer at some point in their lives.  Fifty percent of all dogs over ten years of age develop cancer.  Some breeds are more susceptible to cancer than others (1). Veterinary science has made huge advances in the past 30 years.  When a vet delivers a cancer diagnosis, pet owners have more treatment options than ever.  However, treatment can be costly, and advanced therapies are not widely available outside of large cities.
 
How Cancer Works
A simple way to describe cancer is to call it a disease where cells misbehave.  Damage to the genetic programming of a cell can cause it to function in a disorganized manner. Cancer cells multiply without limitations and change the structure and function of tissues. Even though cancers are categorized according to their location and their expected behavior, each cancer occurrence is unique.  The course of the disease is notoriously unpredictable.  This explains why a single treatment or cure for cancer has been so elusive.
Because no one treatment is effective against all cancers, some researchers have decided to explore prevention.  They are investigating ways to harness the immune system to eliminate cancer cells before they have a chance to multiply and take root in the body.  
 
The Immune System: Security for Your Pet’s Body
The immune system is an animal's biological security guard.  Its job is to recognize and eliminate intruders like bacteria and viruses.  Bacteria and viruses contain proteins that are different from the ones in the animal's cells.  It is these foreign proteins that alert the immune system to an intruder.
Unfortunately, the first time the immune system encounters a new intruder, it can be slow to recognize and respond to the threat.  The better acquainted the immune system is with a threat, the faster and stronger it can react. Vaccines work by familiarizing the immune system with the foreign proteins of a specific intruder.  This way, when the intruder appears in real life, the immune system will recognize it faster and respond in a targeted manner to eliminate the threat.
 
What’s New in Animal Cancer Research? 
Just like bacteria and viruses, cancer cells are intruders.  They contain foreign proteins. Recent research has focused on identifying proteins that are present in cancer cells but absent in normal, healthy cells (2). If a common protein can be identified in many different types of cancer, it can be used to develop a vaccine that prevents multiple cancers. The vaccine will present this target protein to the immune system for familiarization.  Then, whenever a new cancer cell appears in the body, the protein will act as a flag to alert the immune system to its presence. The hope is that the immune system will quickly destroy the abnormal cell before it becomes a tumor.
A few suitable target proteins have been identified.  Preliminary vaccine investigations in mice have demonstrated promising results (2,3).  A 5-year vaccine trial in dogs is currently underway in the United States to see if this technology works in a real-life setting (4,5).  If the vaccine is proven safe and effective at reducing cancer, pet owners may one day have the power to protect their canine companions from one of the leading causes of illness and death in dogs.
 
References
1. Dobson JM. Breed-predispositions to cancer in pedigree dogs. ISRN Vet Sci. 2013;2013:941275.
2. Lopes, A., Vandermeulen, G., & Préat, V. (2019). Cancer DNA vaccines: current preclinical and clinical developments and future perspectives. Journal of experimental & clinical cancer research: CR, 38(1), 146. https://doi.org/10.1186/s13046-019-1154-7
3. Thalmensi, J., Pliquet, E., Liard, C., et al. (2019). A DNA telomerase vaccine for canine cancer immunotherapy. Oncotarget, 10(36), 3361–3372. https://doi.org/10.18632/oncotarget.26927
4. McReynolds, T.  (2019, July). World’s largest canine cancer study would lead to a cancer vaccine for humans.  AAHA Newstat.  Retrieved from https://www.aaha.org/publications/newstat/articles/2019-07/worlds-largest-canine-cancer-study-could-lead-to-a-cancer-vaccine-for-humans/
 
Written by:
Dr. Sperry, DVM, Veterinary Advisor, Pets Plus Us
The information provided and contained herein are the opinions of PTZ Insurance Services Ltd. which are based on external publication. The content is not intended to be a substitute for professional veterinary advice. PTZ Insurance Services Ltd. assumes no responsibility or liability for any loss, claims or damages arising out of the within content.