When it comes to cancer rates in the animal kingdom, elephants are an anomaly. As Popular Science notes, cancer should be more common among larger species, but with elephants, that simply isn’t the case. Only about 5 percent of elephants die from cancer, compared to 11 to 25 percent of humans.

In a new study, published in Cell Reports, University of Chicago researchers found what’s believed to be the genetic source of elephants’ cancer immunity. Elephants, like all mammals, have a gene called LIF that is known to suppress tumors. Humans have one copy of this gene, but elephants have 10 copies, which have developed over 80 million years of evolution. However, only one of those copies, called LIF6, is functional in elephants.

The other LIF copies are essentially dead because they lack a specific piece of DNA to make them function. At some point during the evolutionary process, the LIF6 gene copy turned back on, but scientists don’t know why or when this occurred. This “zombie gene” helps kill mutated cells, in true Night of the Living Dead fashion.

“This reanimation of LIF6 occurred perhaps over 59 million years,” Joshua Schiffman, who studies cancer in elephants but was not involved in the study, told Popular Science. “That’s an amazingly long period of time for nature to modify and perfect an anticancer mechanism.”

Scientists aren’t yet sure how this could be applied to cancer research in humans, but they say it’s a promising start and a creative approach to the problem. While these findings are still fresh and need to be duplicated, it raises the possibility of creating a drug that mimics the function of LIF6.

[h/t Popular Science]