Researchers have identified a gene that appears to solve the mystery of why elephants – who should be at a greater risk of developing tumors because of their size – are not more prone to cancer than smaller animals. According to a report published in Cell Reports by Vincent J. Lynch, PhD, an evolutionary biologist at the University of Chicago, and co-authors, the LIF6 gene works with the TP53 gene to protect elephants against cancer development by killing off damaged cells.
While all mammals carry a similar gene, called LIF, it appears that only elephants possess the LIF6 gene. This gene became dormant through the course of evolution, but researchers speculated that it was “resurrected” when the ancestors of living elephants evolved extra copies of TP53.
The discovery of this “zombie gene” builds on Dr. Lynch’s earlier research, in which he recognized that elephants have 20 copies of the TP53 gene. (Comparatively, humans have only one copy.) This “swarm” of TP53 copies responds aggressively to DNA damage by inducing the death of damaged cells instead of repairing them.
The discovery of this gene, the researchers noted, could provide inspiration for developing new drugs. “It might tell us something fundamental about cancer as a process. And if we’re lucky, it might tell us something about how to treat human disease,” Dr. Lynch told The New York Times.
Sources: The New York Times, August 21, 2018. Vazquez JM, Sulak M, Chigurupati S, Lynch VJ. A zombie LIF gene in elephants is upregulated by TP53 to induce apoptosis in response to DNA damage. Cell Report. 2018;24:1765-76.