AUG 05, 2019 7:46 PM PDT

A Canine Cancer That Began to Spread From One Dog About 6,000 Years Ago

WRITTEN BY: Carmen Leitch

Dogs can get different kinds of cancers, including one that is transmitted by live cancer cells, which spreads through sexual contact, called canine transmissible venereal tumor (CTVT). Researchers have now traced this cancer back to a single dog, a founder that lived sometime between 4,000 and 8,500 years ago. The findings have been reported in Science.

Artist's impression of the 'founder dog' that first gave rise to CTVT. This dog's phenotypic traits were interpreted from the genetic variation found in the DNA of the cancer that it spawned. / Credit: Emma Werner

In this work, scientist Adrien Baez-Ortega of the University of Cambridge and colleagues sequenced tumors from 546 dogs around the world, including two dogs of different breeds from Brazil and Australia that both had CTVT. Their tumor cell genomes had almost two million mutations in common, which aren’t found in normal canine DNA. The scientists found that the CTVT genome has remained very stable over time, and contains variations in its sequence that aren’t in normal canine DNA. This showed that CTVT doesn’t develop in dogs sometimes; it arose one time and has spread ever since, from one dog to another.

The work also suggests that CTVT doesn’t progress much over time. Tumors seem to grow to an optimum state and then stabilize, whichi is unusual because cancerous tumors often pick up new mutations as the cells proliferate. Some of those mutations might not have any impact, while others could be harmful to the tumor. But some mutations can increase growth and resistance to drug treatments.

This work could help researchers learn more about human cancers that grow slowly, and how to limit tumor growth when it doesn’t pose a serious health threat.

"Cancers evolve, and our strategies for managing cancer need to take that into account," commented Carlo Maley, who wrote about this research with Darryl Shibata in Science. In the future, we hope to maintain long-term control over these evolving tumors. CTVT is fascinating because it shows us how cancers might evolve over the long term."

"Most cancers can only evolve for a few decades before they die with their host," Maley added. "CTVT is an incredible natural experiment, which showed us that it doesn't take much for a cancer to reach an optimal state. It is amazing that it did not discover additional adaptations over thousands of years, even as it infected all different breeds of dogs in all different environments around the world."

Learn more about CTVT from the video above.

In other research on unrelated canine cancers, researchers are testing a new vaccine in a trial. Learn more from the video below.

 

Source: AAAS/Eurekalert! via Arizona State University, Science

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
AUG 29, 2020
Cell & Molecular Biology
Together, Two Gut Microbes Have a Nasty Effect
AUG 29, 2020
Together, Two Gut Microbes Have a Nasty Effect
The microbes in the human gut play important roles in our physiology, and they can also contribute to disease. But they ...
SEP 10, 2020
Space & Astronomy
Could There Be Life on Venus?
SEP 10, 2020
Could There Be Life on Venus?
Venus is the hottest planet in our solar system, reaching 465 degrees Celcius- a temperature hot enough to melt lead. Wh ...
OCT 05, 2020
Plants & Animals
Bacteria Caused the Deaths of Hundreds of Elephants
OCT 05, 2020
Bacteria Caused the Deaths of Hundreds of Elephants
African elephants are a threatened species that are increasing in some areas but at risk in many others. There are proba ...
OCT 19, 2020
Microbiology
Microbes in Cheese Use Those Funky Smells to Communicate
OCT 19, 2020
Microbes in Cheese Use Those Funky Smells to Communicate
Cheese is made with microbes, and some of it has a very distinct smell. Scientists have now found that those smells actu ...
NOV 08, 2020
Genetics & Genomics
Drug-Resistant Microbes Persist in Hospitals After Deep Cleaning
NOV 08, 2020
Drug-Resistant Microbes Persist in Hospitals After Deep Cleaning
Researchers have found that drug-resistant bacteria can hang around even after deep cleaning. They used genome sequencin ...
NOV 27, 2020
Microbiology
Understanding Why Flu Can be Fatal
NOV 27, 2020
Understanding Why Flu Can be Fatal
People that have the flu can usually recover on their own. But sometimes, influenza infections can be far more serious a ...
Loading Comments...