Elephants are popular for their big build and quiet nature. In a way, they teach people to stay calm and collected amid the hustles of the jungle called life. Now, researchers are learning another valuable lesson from these gentle giants: how to fight cancer.
When a cell divides, there is always a chance for it to undergo mutation, which can hasten its development. Clusters of mutated cells can accumulate and form into a cancer. This premise suggests that the higher the number of cells a species has in its body, the higher the risk is for it to develop a mutation. Also, the longer a species lives, the higher the frequency of cell division and the chance for mutated growths are.
Researchers have long been fascinated over why large and long-living animals such as elephants, which may weigh up to 7 tons and live up to 70 years, rarely get cancer despite their tremendous number of cells. Less than 5 percent of elephant deaths is due to cancer, while 11 to 25 percent of deaths among smaller framed humans is due to the same ailment.
Another puzzling circumstance—the Peto's paradox—points out that humans and tiny mice have almost the same cancer risk despite the former having to undergo 10,000 cell divisions more than the latter.
In a new study, researchers from the Huntsman Cancer Institute (HCI) at the University of Utah, Arizona State University, and the Ringling Bros. Center for Elephant Conservation investigated how this baffling concept came about.
First, they tried to understand the elephants' defenses by looking at the species' p53 gene, which encodes proteins that monitor DNA for damage. The gene either triggers the cell to repair itself, stop dividing or commit suicide.
Humans only have one pair of p53 while elephants have 20 pairs.
To determine whether the increased number of the said genes has something to do with elephants' low risk of cancer, one group of researchers subjected the elephant cells to DNA-damaging agents and radiation doses, while another group utilized other chemicals and ultraviolet rays.
The results showed the elephant cells all committed suicide instead of trying to repair the damage.
"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 Dr. Joshua Schiffman, co-senior author of the study and a pediatric oncologist at the University of Utah School of Medicine and Primary Children's Hospital. He added that through this approach, the cells are completely killed and thus not given the chance to turn into cancer. The strategy may be a more effective way of dealing with mutated cells.
Schiffman was surprised with the results. He said that additional elephant studies could possibly result in breakthroughs in human cancer treatments.
"Nature has already figured out how to prevent cancer," Schiffman points out. "It's up to us to learn how different animals tackle the problem so we can adapt those strategies to prevent cancer in people."
What now?
Schiffman says examining the blood of other big animals, such as whales, could be interesting since they also have lower cancer risks.
In the end, Schiffman, who is a childhood cancer survivor himself, believes it is vital to persist in finding treatment for patients stricken with the disease.
The study was published in the Journal of the American Medical Association on Thursday, Oct. 8.
Photo: Justin Hall | Flickr
