They may not be the fastest or the smartest or even the scariest, but when it comes to beating cancer, elephants are the superheroes of the living world.
It's a phenomenon that has baffled scientists since the 1970s. After all, at their size, they should have a much higher rate of the disease. The larger a living thing, the more the cells, and the more the cells, the more chance one of them turns out to be cancerous -- which is why tall people are more vulnerable to the disease than short people and why Marmaduke is much more likely to get cancer than the Taco Bell Chihuahua.
And yet, cancer rates among elephants is less than 5 percent, comparable to the rates in much smaller animals. The lifetime cancer mortality rate for humans is about 20 percent.
So what gives? With all those cells on their body, why are more elephants not stricken by the disease?
Scientists may have found an answer.
In a paper published in the journal Cell Reports Tuesday, researchers from the University of Chicago announced they may have discovered one of the cancer protection mechanisms the pachyderms have evolved to deal with every time a cell may be corrupted.
"What we found is that elephants have an extra copy of the gene whose job it is to kill the cell when there is the kind of stress that causes cancer," said Vincent Lynch, an evolutionary geneticist at the University of Chicago in Illinois and an author of the study.
The fact that this gene was even functional was extraordinary -- it was supposed to be non-functional or "dead". Yet somehow this "zombie" gene, called leukemia inhibitory factor 6 (LIF6), had evolved in elephants to come back from the dead and slay any cell that showed damage to its DNA, thus preventing it from becoming cancerous.
This is the second study that has found the differences in elephant genome that may explain the animal's ability to resist the disease.
In 2015, two teams of scientists -- one led by Lynch from the University of Chicago and the other from the University of Utah -- found in elephants 20 copies of a major cancer-suppressing gene called p53 that helps damaged cells repair themselves or self-destruct when exposed to cancer-causing substances.
Both these discoveries could have implications for the human fight against cancer, Lynch said.
"If we understand the function of this gene and all the other genes that makes elephants cancer-resistant, maybe we'll be able to develop drugs that mimic those functions and then use that to treat people with the disease," he said.
And there's hope that over time, scientists will come upon more such discoveries. Other creatures, such as some types of whales, bats and mole rats, also show unusual resistance to cancer, and they have none of the extra genes found in elephants -- which means they must have evolved their very own cancer protection mechanisms.
But don't cheer yet. Even if Lynch's findings in 2015 and 2018 are replicated and confirmed, there's still a long way to go.
"Developing new drug treatments is a very complex process and it takes decades," Lynch said. "We always hear the news that there is some discovery and that a new treatment based on that discovery is five to 10 years away but it's never five to 10 years. So this is going to be a very very long process."
"Of course," he added, "I guess we've been dealing with cancer for billions of years, so you know, a couple of decades isn't that long in the grand scheme of things."