Why do whales and elephants, the largest animals on the planet, never get cancer?


Elephants and whales are some of the largest animals on Earth. Scientifically, larger organisms have more cells and are more likely to mutate and develop cancer. However, this rule does not work for elephants and whales: they almost never develop tumors.

The results of research scientists have turned all ideas about evolution.

A malignant tumor occurs as a result of mutations in healthy cells during division under the influence of the environment or age-related disorders of the body. The altered DNA of a mutated cell triggers its uncontrolled division and turns off the process of apoptosis — programmed cell death.

It is fair to assume that the larger the organism, the more cells it has, which means that the likelihood of the appearance of «wrong» cells is also higher.

A similar rule is true for creatures of the same species. For example,

However, if we consider different types of animals, then the picture changes dramatically. Elephants are prone to cancerous tumors, but

At the same time, as studies show, mutations in animal cells also occur, and occur much faster than in humans. But the rate of DNA repair (repair) in both whales and other mammals is absolutely the same.

This state of affairs in science is called the Peto paradox, after the English epidemiologist, who in 1973 pioneered his

In 2012, American biologists

The TP53 gene produces the p53 protein, which is capable of repairing «sick» cells or destroying them, preventing them from spreading throughout the body. It is a suppressor gene that emerged during evolution specifically for the fight against cancerous tumors. Numerous copies of it have also been found in the remains of extinct mammoths.

It seemed that the creation of a cure for cancer by scientists was not far off. In 2013, genetics from Virginia

The mutated mice did an excellent job with them, showing high resistance to the disease. However, the rodents began to age faster, their fertility decreased, and they died without having time to leave offspring.

Thus, scientists have found an evolutionary correlation between life expectancy and fertility. Humans and humpback whales have the same lifespan. People are more likely to die of cancer, but in the same time they have time to leave more offspring than marine mammals.

If you change the balance and take away several copies of the TP53 gene from the whales, then the animal will simply die out.

However, the researchers are not abandoning their attempts to curb the TP53 gene, because few people want to cope with cancer, but still die earlier due to premature old age. Perhaps one day we can overcome mutations and come up with a cure for cancer.

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