Cancer is an illness that has always been mysterious, even to scientists. Every year thousands of humans and animals die of cancer. But not elephants. That’s right. Elephants rarely become the victim of this deadly disease. But why don’t elephants get cancer?
Experts believe it’s because of the extra copies of the tumor suppressor gene present in an elephant. These genes are named P53 tumor suppressor genes. Another set of proteins has a major role in resisting cancer in elephants, that is, LIF6 genes. Humans have only one pair of tumor suppressor proteins, whereas elephants have over 40.
How does TP53 help prevent cancer in elephants? What are LIF6 genes and their role in preventing cancer in elephants? Do elephants ever die of cancer?
Why Do Elephants Get Cancer Less Often?
Elephants are multicellular organisms, meaning they have more than one cell. Statistically, elephants contain 100 times more cells than humans.
You might think that more cells mean a higher risk of cancer. But Peto’s paradox suggests otherwise.
Surprisingly, elephants have a near to non-existent risk of developing cancer— all thanks to a higher number of tumor suppressor genes in their gigantic bodies.
Researchers have successfully identified the two tumor-killing genes in elephants. Let’s learn more about them!
How Does TP53 Help Resist Cancer in Elephants?
TP53, or Tumor Protein 53, is the ultimate savior in preventing cancer formation. These genes encode a protein that acts by binding to the DNA of a cell, helping prevent cell mutations. That is how TP53 also protects all animals from cancer, including humans.
Humans have only one pair of TP53 genes in their cells. Each pair has two alleles or two proteins that act against the cancer-producing cells.
However, having only one pair of such genes isn’t enough to stand against the deadly disease. Therefore, humans aren’t resistant to cancer.
On the contrary, elephants have around 20 pairs of Tumor Protein 53 genes, hence more warriors against the cancer cells.
That means an elephant’s body has 40 proteins in each cell that have been protecting them against cancer for ages.
These tumor suppressor proteins regulate the rapidly dividing cells and prevent them from further proliferation. It does it either by repairing damaged DNA or causing the cell to die (apoptosis). Therefore, stopping cancer cells from spreading in the first place.
What Is the Role of the LIF6 Gene in Preventing Cancer?
LIF6, or leukemia inhibitory factor, is another tumor suppressor gene in elephant body cells.
These genes, however, in contrast to TP53, are pseudogenes. They stay asleep unless activated by TP53 itself. Yes, they’re like hired guards of TP53 guarding against carcinogens.
These genes act on a cell’s mitochondria, causing them to leak out its proteins and die of suicide (apoptosis) when the DNA is mutated.
LIF6 genes are called “Zombie genes” due to their evolutionary record.
Scientists discovered that these genes disappeared millions of years ago and mysteriously became active again.
Hopefully, these anti-cancer genes will prove helpful against human and animal cancer cells in the future.
What Does the Research Say?
According to the research, only 5% of elephants die of cancer. Approximately 11 to 25% of deaths occur in the human population because of cancer.
Researchers experimented to prove the existence of tumor resistance in elephant genes. The clinical trial included cells from patients with Li-Fraumeni syndrome (unhealthy genes), healthy human genes, and cells from elephants.
Patients with Li-Fraumeni syndrome have a 90% risk of developing cancer in their lifetime due to the incomplete copy of TP53 genes. Hence, including these patients in the study would prove even more beneficial.
All these cells were exposed to mutated DNA. The research concluded that elephant genes self-damaged the mutated DNA at twice the rate of healthy human cells.
Moreover, the highly protective elephant genes destroyed the mutated DNA more than five times the rate of unhealthy human genes. Sounds impossible. But it’s true!
Furthermore, scientists believe that the gestation period of elephants (22 months) also plays a crucial role in preventing cancer.
So much time to create a whole new animal comes with many other benefits, such as producing extra copies of anti-cancer genes.
Final Words On Why Elephants Don’t Get Cancer
Elephants have massive bodies meaning more cells than humans. Yet these giant mammals don’t get cancer—all thanks to the extra pairs of genes constantly fighting against cancer cells. The two anti-cancer genes we learned are TP53 and LIF6.
Both these genes prevent the turnover of cells either by self-destructing the mutated cells or by releasing substances to repair the damaged DNA.
Elephants are resistant to cancer because they have 40 tumor suppressor proteins in their cells. In contrast, humans have only one pair of TP53 genes.
Now we know elephants are not only unique because of their huge size, but their ability to resist cancer is also mind-blowing.
Can Elephant Gene Help Against Cancer in Humans?
If we think about it, elephant genes can help against cancer in other animals. However, research has yet to prove this so far. Researchers are still working on filling this gap in the field of cancer.
What does Peto’s Paradox Have to Do With Elephants?
In the past, people believed that having more cells in a body somehow increased cancer risk. Richard Peto burst this myth bubble in his research, popularly called Peto’s Paradox. He suggested that it’s not the size but the time (duration) of a carcinogen exposure that causes cancer. The longer the duration, the higher the risk of cancer.
How Does Cancer Spread?
In simple terms, cancer takes its roots from the mutated genomes. DNA can get triggered due to many reasons, such as chemical toxins, UV light exposure, radiation, and sometimes, genetic inheritance can be one of the reasons. They can trigger excessive turnover of cells. These rapidly dividing cells are what we call “cancerous cells.”