For several years, pediatric oncologist and childhood cancer survivor, Dr. Joshua D. Schiffman, would often find thoughts about Peto’s Paradox running through his head. The paradox questions why large animals, like elephants, have a significantly lower rate of getting cancer than smaller animals, despite having a higher number of cells. An elephant can live to 70 years old and retains 100 times as many cells as a person, yet the rate of cancer mortalities is less than five percent compared to human’s, who have a cancer mortality rate of between 11 and 25 percent.
It wasn’t until Schiffman was at the zoo with his three children when an elephant caretaker was explaining how the creatures flap their large ears to circulate blood throughout the body that he started thinking about the paradox’s significance to his research. He asked the caretaker, Eric Peterson, about getting access to some elephant blood, leading to him publishing a study in the Journal of the American Medical Association (JAMA) Thursday with co-author Carlo C. Maley, an associate professor at Arizona State University.
“I think the real takeaway for me is essentially that evolution had over 55 million years to figure out how to prevent cancer in elephants, and now the challenge is to learn how to apply that knowledge to our own human patients.” Schiffman told CBS News.
The study is a collaboration between the zoo, the Huntsman Cancer Institute at the University of Utah (where Schiffman works), Primary Children’s Hospital, and the Ringling Bros. Center for Elephant Conservation. It found that elephants have 38 additional modified copies, or alleles, of a gene that encodes p53, which is a tumor suppressor. By comparison, humans only have two of the alleles, according to CBS. In fact, the study revealed that elephants are somewhat of a cancer-fighting machine. The creatures kill damaged and cancer-prone cells at double the rate of humans. Schiffman’s lab works closely with patients of Li-Fraumeni Syndrome, a rare hereditary disorder that increases the risk of developing certain cancers, such as breast cancer and a form of bone cancer known as osteosarcoma. The study compared the cells of these patients with cancer-free people as well as elephants, finding that elephants killed pre-cancerous cells at a rate two times better than healthy humans, and five times greater than people with the syndrome.
The Ringling Bros. Center for Elephant Conservation contacted Schiffman to give him a chance to examine their herd of Asian elephants, which is the largest in North America. He had previously only studied blood samples from African elephants, so this allowed him to see if the cancer-fighting genetic proficiency was found outside his sample group. Fortunately the answer was yes, which prompted the circus’ parent company, Feld Entertainment, to announce a new funding effort on Thursday to support more elephant research. The company also stated that they will donate $10,000 to the local children’s hospital or treatment center in each of the 50 cities it tours through next, and The Ringling Bros. Children’s Fund will then match each donation with an additional $10,000 to the Primary Children’s Hospital Pediatric Cancer Research Program.
“Ironically, the zoo is less than a mile from where I live and not much more than a couple miles from where I work,” Schiffman said. “Every day I would drive by the zoo without realizing that the potential secrets to cancer prevention were right behind the zoo walls.”
On top of helping us win the battle against cancer, the findings emphasize the importance of elephant conservation, says Schiffman, who believes that further elephant study could potentially mean new developments in human cancer treatments. Furthermore, he added that there is a theory that humans develop cancer more frequently because they “don’t live the lifestyles they were evolved to live.” Thanks to a general lack of exercise and an indulgence in unhealthy food, modern humans are on a bit of an “unnatural” path.