Cancer is something we humans can’t catch from one another. Some animals, though, aren’t so lucky. Tasmanian devils, along with dogs and shellfish, are all capable of spreading different types of cancer to one another.
Contagious cancer has been a huge problem for devils, which live only on Tasmania, an island off Australia’s southeast coast. In 1996, researchers first noticed the animals all had the same cancerous facial tumor (paywall). Unlike most forms of cancer, which arise from genetic mutations within an individual, these tumors are actually all the same cancerous tumor hopping from host to host. Tasmanian devils are aggressive toward one another by nature: As they bite each other, tumor cells on the mouth of one are passed along to the other, where they can start to grow. Scientists called the illness Devil Facial Tumor Disease (DFTD). In January of this year, they discovered a second type of tumor contributing to DFTD.
Usually, the lumpy, red or pink masses around the devil’s mouth and necks are fatal within a few months because they either make the animal to unable to feed, leading them to starve to death, or spread internally and cause other organs to stop functioning. In less than 20 years, the population of Tasmanian devils has dropped 80% because of DFTD.
The animals may able to pull themselves off the fast track to extinction—with some help from evolution. On Aug. 30, a team from the University of Tasmania, Washington State University, and others published work in Nature Communications that showed that some groups of devils appear to be resistant to DFTD.
The discovery came about after researchers began investigating certain geographic groups of Tasmanian devils that seemed to be less affected than DFTD than others. They looked at genes in about 10,000 tissue samples of devils, some collected before the disease outbreak and some after, and were able to spot seven genetic mutations shared by two different devil populations that appear to prevent these groups from getting fatally sick.
“Quite a number of the genes we found are involved in cancer and the immune system,” Brendan Epstein, a biologist at Washington State University, said in a press conference. The research team believes the recurring mutations they found may speed up the devils’ immune response to introduced cancer cells from another animal.
In the short term, this work spells out good news for Tasmanian devils, but the researchers hope it can eventually lead to clinical developments. Because most of the tumors in DFTD are genetically similar—National Geographic described it as though “every infected devil has in effect received a tissue transplant from the original cancerous devil”—it’s kind of like studying “one very long-lived human tumor in a single individual,” Andrew Storfer, a biologist at Washington State University and co-author of the paper, said in the press conference. “We’re hopeful [some of these genes] give us information about human cancer as well.”