This article recently came out on Nature.com.
Dog cancer traced back to wolf roots
200-year-old tumour has mellowed with age.
A contagious form of dog cancer that is transmitted by sex has been traced back to its probable origins: a single wolf or dog that lived in Asia more than 200 years ago.
The disease seems to have been more aggressive in its past, the researchers say. This is unusual most cancers become worse over time. If we could work out how and why the disease became less deadly, it may help in finding cancer treatments.
Most cancers are formed when an organism’s own cells grow out of control. But canine transmissible venereal tumor (CTVT) is spread by tumor cells that move from dog to dog during sex. The disease attacks the face and genitals, but usually clears up within months.
Researchers have suspected that the diseased cells originated in a single animal. The cancer now affects dogs in Japan, the United States, Europe, China, the Far East, the Middle East and parts of Africa.
Claudio Murgia of University College London (UCL) and his colleagues examined the DNA of tumor cells from 16 unrelated dogs being treated for CTVT in Italy, India and Kenya. “We can tell that the tumor didn’t belong to the dog because it’s genetically different from its host,” says team member Robin Weiss, a virologist at UCL.
To find out where the tumours came from, the team analysed more than 400 dogs from 85 different breeds. The cancer’s DNA was most similar to modern wolves. There was also a link to Asian dogs such as shitzus.