Elephant genes 'can stop cancer'
Elephants may hold the key to fighting cancer after scientists found that they carry a large number of genes that suppress tumours.
Researchers have long puzzled over why elephants do not develop cancer, even though they have lifespans that are similar to humans, living for around 70 years.
Now a team at the University of Chicago has found that elephants carry 20 copies of a tumour-suppressing gene called TP53. Most other species, including humans, only carry one copy.
The scientists found that the extra copies of the gene heightened sensitivity to DNA damage, which causes the cells to quickly die off when damaged before they can go on to reproduce and form deadly tumours.
The study found that when the same genes were activated in mice, they developed the same cancer resistance as elephants. Dr Vincent Lynch, the study author, said: "A major constraint on the evolution of large body sizes in animals is an increased risk of developing cancer."
Similarly, organisms with long lifespans have more time to accumulate cancer-causing mutations. However, elephants do not face an increased risk of cancer - a discovery dubbed "Peto's Paradox", named after Richard Peto, the Oxford scientist who found that the incidence of cancer does not correlate with the number of cells in an organism.
Now scientists believe they know why. Elephants are the first species found to have 20 copies of the TP53 gene, which stops cancer growth by spotting when cells are damaged.
"These results suggest that an increase in the copy number of TP53 may have played a direct role in the evolution of very large body sizes," added Dr Lynch.
The researchers hope it may be possible to use this newly discovered protein to develop treatments that can help stop cancers from spreading or even developing in the first place.