Elephants Rarely Get Cancer: Gene Copies Suppress Tumor Growth

Elephants rarely ever get cancer, but this goes against what we know in science to be true.

Elephants carry many more cells in their bodies than humans and more cells typically mean an increased risk of cell division--a process that leaves room for lethal errors. Yet elephants' cells carry 20 copies of a gene known as TP53 when humans only carry two in each cell of this well-known tumor suppressor. We receive one a piece from our parents. 

"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," co-senior author Joshua Schiffman, M.D., of the Huntsman Cancer Institute at the University of Utah, said in a news release. "It also coordinates cell death or suicide."

In this recent study, researchers compared cancer rates in 36 mammals, including elephants. They examined 14 years of data from the San Diego Zoo during necropsies, which showed that cancer risk did not increase with the animals extensive body size.

Afterward, the researchers collected blood samples from six Asian elephants, two African elephants, 10 people with Li-Fraumeni syndrome (a rare cancer predisposition characterized by a a faulty copy of TP53) and 11 people without Li-Fraumeni syndrome, according to Live Science, exposing the blood cells to radiation.

When healthy cells are exposed to radiation, TP53 causes events that lead up to the death of the cell. (But don't worry--this is a good thing because it lowers cancer risk.)

Findings revealed that those with Li-Fraumeni syndrome had the least cell death (2.7 percent) while healthy humans had cell death at about 7.2 percent. Elephants, on the other hand, came in at 14.6 percent cell death, according to researchers.

"Compared with other mammalian species, elephants appeared to have a lower-than-expected rate of cancer, potentially related to multiple copies of TP53," researchers noted. "These findings, if replicated, could represent an evolutionary-based approach for understanding mechanisms related to cancer suppression."

While every year there are over 16,000 new cancer patients in the United States alone, less than 5 percent of elephants develop cancer when compared to 25 percent of humans, according to study authors. With future studies, researchers are hopeful that this information could lead to new cancer treatments.

The study was published in the Journal of the American Medical Association (JAMA).

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