UCL News


Study Finds That a Type of Cancer in Dogs Is Contagious

11 August 2006

Scientists in England have gathered definitive evidence that a kind of cancer in dogs is contagious - a peculiar exception to the age-old medical wisdom that you can't "catch" cancer.

A cancer cell is usually an animal's or person's own cell that - because of exposure to a virus or other environmental agent - has broken free of normal growth controls. Cancer-causing viruses may spread from person to person, but the cancer does not.

But the dog cancer, known as Sticker's sarcoma, is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other. …

Today's worldwide distribution of Sticker's tumors represents a single colony of cancer cells, the new research concludes. …

"I rather thought we might disprove this, but it came out the other way around," said Professor Robin Weiss [UCL Infection & Immunity], who led the study appearing in today's issue of the journal 'Cell'. "It is clearly a dog tumor cell behaving absolutely like a parasite." Weiss called the tumor transmission trick "a curiosity of nature." …

Weiss and his colleagues did genetic studies on the tumor cells from 40 dogs with Sticker's sarcoma, collected from five continents. The researchers showed that the cells are not genetically related to the dogs they are in - proof that they did not arise from the dogs' own cells.

They also showed that all the tumor cells, no matter where they were collected, are clones of each other. That is, they are all progeny of the same parent cell.

Further genetic studies by Weiss's team suggested that the parent cell probably arose in a domesticated dog of Asian origin - perhaps a husky - hundreds of years ago, and perhaps more than 1,000 years ago. Since then, the cancer has perpetuated itself by jumping from one dog to another. …

Rick Weiss, 'Washington Post'