What Protects Elephants From Cancer?

Credit: Patrick Bouquet 

Credit: Patrick Bouquet 

Elephants are long-lived, and rather large. Given their size and longevity, scientists have pondered what protects them from cancer for a long time. Thanks to new research, we now know. 

A mystery unlocked

Cancer is a big problem. A staggering 1 in 2 people born after 1960 in the UK are predicted to develop cancer at some point in their lifetime. We may be living longer, but the extra years are coming with a raised cancer risk. We may be getting better at treatment, but we're still finding out exactly what causes it, and how we can prevent it from being a danger altogether. 

Enter elephants. Biology had to find ways to deal with cancer to enable any 'longer lived' organisms to exist and while humans rarely get cancer before 50, some fellow mammals do even better. We've covered whales before, but elephants also exhibit interesting protection. 

New results from a long study on elephant biology have revealed that they have not 1, or 2, but 38 copies of a gene called p53. The same gene acts as a strong tumour suppressor in humans, but we only have 2 copies. Patients with Li-Fraumeni Syndrome only have 1 working copy of p53, and have staggering cancer rates of 90%. You can see why having 38 copies could be a big help. They're also better at killing off damaged cells at risk of becoming cancerous. When an elephant cell and human cell were exposed to radiation damage in the lab, the elephant's were twice as likely to commit suicide in response, shielding the organism from harm.

"Nature has already figured out how to prevent cancer. It's up to us to learn how different animals tackle the problem so we can adapt those strategies to prevent cancer in people. It's as if the elephants said, 'It's so important that we don't get cancer, we're going to kill this cell and start over fresh. If you kill the damaged cell, it's gone, and it can't turn into cancer. This may be more effective of an approach to cancer prevention than trying to stop a mutated cell from dividing and not being able to completely repair itself."

                      Credit: jinterwas, Flickr

                      Credit: jinterwas, Flickr

Despite having 100 times more cells, elephant cancer mortality is less than 5%, compared to 11-25% in humans. Over time, evolution has duplicated the original p53 gene and provided them with increased resistance. This may be something we can replicate and learn from; in the future we could conceivably engineer our genome to optimise protection. Elephants aren't the only organism we can learn cancer secrets from, as other animals like the bowhead whale and the naked mole rat are also remarkably resistant. p53 isn't the only piece in the puzzle, but it's another important insight. 

Read more at ScienceDaily