‘Zombie gene’ could explain why elephants rarely get cancer

[B]igger animals, which have more cells, should have greater occurrences of cancer. By that reasoning, elephants, with hundreds of times more cells than smaller mammals, should suffer from the disease at much higher rates. But that isn’t the case. Now, a study in the journal Cell Reports offers new clues as to why—and the key may be a recently revived “zombie” gene.

…

[Author Vincent] Lynch and his colleagues began searching for other genetic differences in elephants compared to small-bodied mammals, specifically, for genes with extra copies. One in particular stood out: Leukemia Inhibitory Factor or LIF.

…

Lynch thinks that LIF6 may also serve another function: slaying damaged cells. Most mammals—from the tiny pika to the massive minke whale—have just one copy of LIF. But elephants and their close relatives, including the manatee and the groundhog-like hyrax, have many.

…

LIF6 appeared in elephant genes some 59 million years ago, the study authors suggest. And initially, it was likely a useless, broken gene. But as elephants’ proboscidean ancestors evolved, so, too, did the gene. It was eventually reawakened as a working “zombie” gene—a change that may have helped elephants reach such momentous sizes unrestricted by cancer.

…

The ultimate hope is that studying animals’ cancer defenses can aid in the development of cancer treatments for humans.

Read full, original post: Cancer Rarely Strikes Elephants. New Clues Suggest Why