Elephants could hold clues to killing cancerous cells

Elephants, with many times more cells in their bodies than humans, should be more prone to getting cancer, but the opposite is true.

However elephants do not face an increased risk of cancer – a discovery dubbed “Peto’s Paradox” named after Sir Richard Peto, the Oxford University scientist who found that the incidence of cancer does not correlate with the number of cells in an organism.

Scientists hope that by decoding the cancer-fighting skills of the world’s biggest land animal they might gain new insights into how to better fight human disease.

Most people have two copies of a gene that codes for p53 – a protein Schiffman calls the “guardian of the genome”.

Humans naturally inherit a pair of TP53 from their parents, one from their mother and one from their father.

“These genes actually kill more than twice as many damaged cells as our genes do”, Schiffman said.

They then subjected human and elephant cells in the lab in radiation, expecting to see human cells die before elephant cells did. The gene helps damaged cells fix themselves or self-destruct when exposed to cancer-causing substances.

But Prof Mel Greaves, from the Institute of Cancer Research in London, says we should focus on why humans have such high levels of cancer.

The researchers also compared the elephant blood to the blood of people with Li-Fraumeni Syndrome, which is a disease where a person only has one copy of p53, which puts them at an over 90% risk of developing cancer.

“If elephants were not protected from cancer, the species would risk extinction because all young and non-reproductive elephants would be at such high risk to develop and succumb to cancer before they could pass on their genes”. Cancer involves uncontrolled cell growth. It detects stress or damage in the cell, and stops the cell from dividing until the stress has passed or the DNA is repaired.

Dr Lynch said: “It may be possible to develop a drug that mimics the function of the TP53 gene”.

To try to figure out p53’s role, Schiffman’s team collaborated with Utah’s Hogle Zoo and the Ringling Brothers Center for Elephant Conservation. “It’s up to us to learn how different animals tackle the problem so we can adapt those strategies to prevent cancer in people”, he said in a news release from the Huntsman Cancer Institute.

The work was published Thursday in the Journal of the American Medical Association. This sparked his attention even further, as his patients include children with incomplete p53 genes due to a condition called Li-Fraumeni syndrome.

What weighs upwards of 14,000 pounds, can live well past 70 years, and nearly never gets cancer?

The lower-than-expected cancer rate in elephants may be related to their multiple copies of TP53, the investigators proposed.

The p53, discovered 35 years ago, has always been known to suppress tumours by signalling cells that have acquired genetic damage to commit apoptosis, or cellular suicide. With the result of a study recently made in elephants, the cure for cancer in humans may be at arm’s reach. “For instance, most human cancers … are associated with lifestyles that are not found among animals, such as smoking, reproductive, dietary, and sun soaking habits”.

“The enormous mass, extended life span and reproductive advantage of older elephants would have selected for an efficient and fail-safe method for cancer suppression”, the researchers wrote in the study.