Elephants and Cancer: Disease Is Rare Because of Tumor-Suppressing Gene

Elephants rarely get cancer because of multiple copies of a critical gene that protects cells, a finding that could lead to new ways of controlling the disease, according to a study published recently in the Journal of the American Medical Association.

Elephants have 20 copies of what is called the TP53 gene, which cancer researchers say creates a protein that suppresses tumors, the Los Angeles Times reported. Only one copy of this gene, called the "guardian of the genome" by some scientists, can be found in humans.

"Compared with other mammalian species, elephants appeared to have a lower-than-expected rate of cancer, potentially related to multiple copies of TP53," the study's authors wrote.

"Compared with human cells, elephant cells demonstrated increased apoptotic response following DNA damage. These findings, if replicated, could represent an evolutionary-based approach for understanding mechanisms related to cancer suppression," the study continued.

Dr. Joshua Schiffman, a pediatric oncologist at the Huntsman Cancer Institute in Salt Lake City, told the Los Angeles Times that TP53 plays the role of first responder to DNA damage.

"When there is DNA damage, it rushes onto the scene and stops your cells from dividing so the DNA can be repaired," Schiffman, the senior author of the elephant study, said. "It also coordinates cell death or suicide."

According to zoo records of 644 elephants, less than 5 percent of elephants died of cancer. By contrast, 11 to 25 percent of humans get cancer, even though elephants weigh hundreds of pounds more and have many more cells that could mutate and become cancerous, according to The New York Times.

The Times wrote that University of Chicago evolutionary biologist Vincent J. Lynch and a team of researchers came up with the same conclusion about TP53 in a draft paper posted on bioRxiv. The research is being reviewed by the science journal eLife, The Times noted.

"We show that several of the TP53 retrogenes are transcribed and translated and contribute to an enhanced sensitivity of elephant cells to DNA damage and the induction of apoptosis via a hyperactive TP53 signaling pathway," Lynch's study abstract reads.

Schiffman told the Los Angeles Times the next step will be to learn how TP53 can help human defenses and may create drugs that mimic the actions of TP553.

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