“Zombie gene” helps elephants resist cancer

Avatar By Joseph Scalise | 2 years ago

Scientists from the University of Chicago and the University of Utah may have figured out why so few elephants contract cancer, according to a new study in the journal Cell Reports.

Though 17 percent of humans die from cancer worldwide, less than 5 percent of captive elephants succumb to the disease. That is strange because, not only do elephants live for 70 years on average, they also have 100 times as many potentially cancerous cells.

To analyze that, the researchers in the study took a close look at human and elephant makeup.

While they knew humans had one copy of the master tumor suppressor gene p53 — which enables animals to recognize unrepaired DNA damage and prevent it from developing into cancer — the team found that elephants have a staggering 20 copies of p53. That makes their cells much more sensitive to damaged DNA and enables damaged cells to kill themselves quickly.

In addition, the research showed elephants have an anti-cancer “zombie gene” as well.

“Genes duplicate all the time,” said study co-author Vincent Lynch, assistant professor of human genetics at the University of Chicago, according to Phys.org. “Sometimes they make mistakes, producing non-functional versions known as pseudogenes. We often refer to these dismissively as dead genes.”

During the research, the team looked at elephant dead genes and found the beasts have a former pseudogene known as leukemia inhibitory factor 6 (LIF6) that somehow evolved a new on-switch. That basically means it came back from the dead. In that resurrected state, the gene — once activated by p53 — can respond to damaged DNA by killing the harmful cell.

That is important in the fight against cancer because the gene acts in response to genetic mistakes and shuts down cells before they can turn dangerous.

Scientists found that LIF6 emerged when the small, groundhog-sized precursors to modern elephants first began to grow. That process — which started between 25 to 30 million years ago — may have enabled modern elephants to grow to their enormous sizes.

That is because the genes would have allowed the animals to increase in size without making them susceptible to cancer-causing mutations.

This new information is interesting from a biological standpoint, but the team hopes it will have implications beyond elephants. They plan to study the animals more in the future and see how LIF6 could relate to humans.

“It might tell us something fundamental about cancer as a process,” added Lynch, according to The New York Times “And if we’re lucky, it might tell us something about how to treat human disease.”