Could Elephants Help Us Find a Cure for Cancer?
While the lives of elephants are often cut short by poachers and hunters, they rarely are the victims of a common killer of humans: cancer.
This is surprising, since elephants have 100 times more cells – all with the potential to mutate and become cancerous – than humans do. Elephants, if they’re lucky, have a life span of 50 to 70 years, yet their cancer mortality rate is less than 5 percent. For humans, it’s up to 25 percent.
“By all logical reasoning, elephants should be developing a tremendous amount of cancer, and in fact, should be extinct by now due to such a high risk for cancer,” said Dr. Joshua Schiffman, pediatric oncologist at Huntsman Cancer Institute at the University of Utah School of Medicine and Primary Children’s Hospital, in a news release Oct. 8.
Why is their cancer risk so incredibly low? According to a new study co-authored by Schiffman, elephants have 20 pairs of the p53 gene, which suppresses the growth of tumors and is critical in preventing cancer. Humans, on the other hand, have only one pair of this gene.
The study’s researchers were from the University of Utah, Arizona State University and the Ringling Bros. Center for Elephant Conservation (which seems kind of ironic, given the company’s long history of mistreating circus elephants). Blood samples were obtained during routine wellness checks of African elephants at the Hogle Zoo in Salt Lake City and Asian elephants at the Ringling Bros. Center for Elephant Conservation in Florida.
The researchers extracted white blood cells and zapped them with radiation and chemical treatments that damage DNA, a typical trigger of cancer. But instead of mutating, the damaged cells destroyed themselves.
“It’s as if the elephants said, ‘It’s so important that we don’t get cancer, we’re going to kill this cell and start over fresh,’” Schiffman said. “If you kill the damaged cell, it’s gone and it can’t turn into cancer. This may be more effective of an approach to cancer prevention than trying to stop a mutated cell from dividing and not being able to completely repair itself.”
The researchers also compared the elephants’ blood cells with those of people with Li-Fraumeni Syndrome – an inherited condition that leaves them with only one active copy of p53 and more than a 90 percent lifetime risk for cancer – as well as blood cells from healthy, cancer-free people.
When exposed to radiation, the elephants’ blood cells self-destructed at twice the rate of healthy human cells and more than five times the rate of Li-Fraumeni cells, supporting the idea that having additional p53 genes offers more protection against cancer.
“Nature has already figured out how to prevent cancer,” Schiffman said. “It’s up to us to learn how different animals tackle the problem so we can adapt those strategies to prevent cancer in people.”
At least one cancer expert is skeptical. Mel Greaves, a professor at the Institute of Cancer Research in London, told BBC News the focus should be on why humans have such a high level of cancer.
“In terms of adaptive mechanisms against cancer, we have the same as a chimp, but we get a lot more cancer than a chimp,” Greaves said. “I think the answer is humans are completely unique as a species in having very rapid social evolution in a short period of time.”
Greaves added that, unlike elephants, humans engage in unhealthy habits such as poor diets and tobacco.
“You’ve never seen an elephant smoke!” he said.
Regardless, if this study’s discoveries actually do help pave the way to a cancer cure, how bittersweet that elephants, who have been driven to near extinction by people, could hold the key for prolonging human life.