You’ve heard that elephants never forget, but did you know they almost never get cancer either?
It turns out just 4.8% of known elephant deaths are related to cancer. For humans, cancer-related deaths are much higher — between 11% and 25%, scientists say.
The low cancer rate among elephants is particularly intriguing because all things being equal, elephants should get more cancer than we do.
Elephants have about 100 times more cells than humans, and they live for about 70 years. That gives a lot of cells a lot of chances to mutate and become malignant over the course of a pachyderm’s lifetime.
Scientists have spent decades wondering why elephants and other large mammals don’t get cancer more often than smaller mammals. This problem even has a name — Peto’s paradox.
Now, new research has uncovered the secret to our big-eared friends’ cancer-fighting prowess.
In a study published this week in the Journal of the American Medical Assn., scientists reveal that African elephants have 20 copies of a gene called TP53. This gene is prized by cancer researchers because of its ability to create a protein that suppresses tumors; in fact, scientists often refer to it as the “guardian of the genome.”
Humans, on the other hand, have just one copy of TP53.
The crucial gene keeps cells safe from cancer in two ways, according to Dr. Joshua Schiffman, a pediatric oncologist at the Huntsman Cancer Institute in Salt Lake City and a senior author of the study.
“When there is DNA damage, it rushes onto the scene and stops your cells from dividing so the DNA can be repaired,” Schiffman said. “It also coordinates cell death or suicide.”
Humans inherit one allele of TP53 from each of their parents, and both of them must be functional to fight off cancer. Studies show that if one of the alleles is defective, cancer is certain to develop sooner or later.
(Click here to read the full article, written by Deborah Netburn, LA Times)