Why don't whales and elephants get cancer?

Weather of Arabia - While some living creatures suffer from tumors and cancers that shorten their lives and perhaps end them, we find whales and elephants safe from this difficult disease. Despite the huge bodies of whales and elephants, which make them good prey for cancers, they do not get them.

Why do some organisms get cancer and others don't?

Cancer is considered a major cause of death in humans, and it kills about 10 million people annually. On the other hand, we find some mammals immune to this disease, as if they have a strange ability to avoid it. While foxes and tigers are susceptible to it and it is a major cause of death for dogs and cats, sheep and antelope are not. Also, bats are also considered to be well protected against cancer, unlike mice, which are susceptible to it

According to a report by The Guardian, whales and elephants have a large number of cells, so they are “supposed” to be more susceptible to developing tumors and cancers, but in fact they do not get cancer. This paradox is called the "Petto paradox" after the British statistician Richard Petot who first outlined it. To become the focus of investigations by scientists at the Wellcome Sanger Institute in Cambridge, United Kingdom. They work with researchers from a number of centres, including the Zoological Society of London.

The larger bodies of whales and elephants are supposed to be more susceptible to cancer

“Cancer is a disease that arises when a cell in the body undergoes a series of mutations in its DNA, causing it to begin dividing uncontrollably, and the body's defenses are unable to stop this growth,” said project leader Alex Kagan. He added: "When the number of cells in the body of an organism increases, the risk of cancer increases, and this applies to humans."

This idea is supported by Simon Spiro, an expert in wildlife veterinary pathology at the Zoological Society, who said: “The cells can be thought of as lottery ticket tickets: the more there are, the greater the chance of winning the jackpot, and in this case, the prize is cancer. “So, if you have an organism that has, say, a thousand times more cells than a human, it would be expected to have a thousand times greater risk of developing cancer.”

From this perspective, there are some species of whales that should not live for a long time without developing cancer, since they carry a large number of cells, talking about hundreds of quadrillions compared to humans who carry only trillions. However, this is not clearly evident, as bowhead whales live an average of 100 to 200 years, for example, while elephants have an average lifespan of about 70 years. However, compared to humans, they all have thousands of times more cells, each a potential starting point for a mutation that could lead to cancer.

In addition to what was mentioned, it was discovered that at the end of life, about 3,200 mutations accumulated in all the different animals that were studied. Regarding this discovery, Kagan said: “The astonishing number of mutations at the end of the lives of these diverse animals is astonishing, although it has not yet been determined whether this could be a cause of the aging process.”

However, it is not entirely clear how long-lived organisms manage to slow down the rate at which mutations appear in their DNA. Also, mutation rates have been linked to age only for animals with low to middle ages.

"We are only able to study creatures that have naturally died, and this means that data on long lifespans will not be abundant. We will have to wait for that data," explained Simon Spiro.

In addition, the first phase of Project Sanger began targeting mammals only. Now, the project extends to include plants, insects and reptiles.

“Social insects like ants are particularly interesting,” Kagan said. “Worker ants and the queen have the same genome, but the queen lives for up to 30 years, while worker ants last a short period of one to two years. This suggests that the queen may be "It has a better DNA repair activation mechanism, although other explanations are possible."

Kagan noted that their research suggests that mice, which are typically used in cancer experiments, may not be the best model for research because of their very short lifespan.

"We can now look at longer-living species that may be more relevant and be useful models for understanding cancer resistance," he added.

Scientists stress that the crucial point is that linking mutation rates, tumors and aging provides new understanding of both processes, and could contribute to improving cancer screening and developing treatments that may contribute to mitigating the effects of aging.

Source: arabicpost