Elephants rarely get cancer and this is a mystery that has dumbfounded scientists for decades. A study led by researchers at Huntsman Cancer Institute (HCI) at the University of Utah and Arizona State University, and including researchers from the Ringling Bros. Center for Elephant Conservation, may have found the answer.
According to a study, published in The Journal of the American Medical Association this week, elephants have the ability to fight cancer. Cancer is caused by mutations in a cell’s DNA that produce faulty instructions leading to uncontrolled growth. Elephants have evolved extra copies of a gene encoding a tumour suppressor, p53, that fights cancer. It was also found that elephants may have a more robust mechanism for killing damaged cells at risk for becoming cancerous.
“Nature has already figured out how to prevent cancer. It’s up to us to learn how different animals tackle the problem so we can adapt those strategies to prevent cancer in people,” says co-senior author Joshua Schiffman, M.D., pediatric oncologist at Huntsman Cancer Institute, University of Utah School of Medicine, and Primary Children’s Hospital.
There is a common school of thought that considers the more cells an organism has, the more likely a fault or mutation will arise and result in cancer. Elephants have 100 times as many cells as people and so they should be 100 times more likely to have a cell slip into a cancerous state and trigger the disease over their long life span of 50 to 70 years. However, only around 5% elephants will develop cancer.
“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,'” says Schiffman. “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 results beg the question, do elephants have low cancer rates, or do humans have extraordinarily high incidences of cancer, with 15-20% of the population being affected. Schiffman’s argument: “In terms of adaptive mechanisms against cancer we have the same as a chimp, but we get a lot more cancer than a chimp. I think the answer is humans are completely unique as a species in having very rapid social evolution in a short period of time.” He also pointed to unhealthy habits that increase the risk of cancer, such as obesity and smoking. The key to the answer could be the menopause. Most species remain reproductively active until they die, whereas humans can live for decades after being reproductively active and therefore, there is little evolutionary pressure to prevent cancer.
Whatever the answer is to cancer, this research holds tremendous promise. “If elephants can hold the key to unlocking some of the mysteries of cancer, then we will see an increased awareness of the plight of elephants worldwide. What a fantastic benefit: elephants and humans living longer, better lives,” said Eric Peterson, elephant manager at Utah’s Hogle Zoo.