"A tall person has a higher risk of cancer than a short one"

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Is cancer a human-only disease? Is its cause due to civilization? If humanity disappeared, so would cancer? The answer to all these questions is no. A resounding no. For about ten years it has been known that a species of trout called Plectropomus leopardus suffers from skin cancer. This type of fish inhabits the so-called Great Barrier Reef, which is located just below a huge ozone hole. Ozone in the upper layers of the atmosphere, as we know, works as a protective cream against ultraviolet radiation from the sun; The lack of this gas causes a predisposition for the development of skin cancer not only in humans, but also in other animals such as coral trout.

There hasn't always been cancer on Earth. In fact, disease appears, like death, with multicellular organisms. All multicellular organisms can suffer from cancer. Only single-celled organisms are saved. It is required to be a multicellular living being to have cancer. It is in this type of structure where the uncontrolled proliferation characteristic of cancer occurs. But you don't need to have many cells to suffer from it. Nor do you have to be an animal to suffer from tumors. Plants suffer from cancer.

Plant tumors are different. Thus, they do not produce metastases, they are more local: because the cells do not move along the plant, tumors are characterized by a local growth such as a lump, for example, on the crest of a cactus. By not producing metastasis, these tumors do not kill the plant that suffers them. Plants also do not have vital organs, such as the brain or lung, which when affected by cancer endanger the life of the animal.

Plant cells have a more rigid structure, different from animals, which is called "wall" and that keeps them fixed in place and does not allow, in the event that a cell becomes a tumor, that it travels or invades neighboring ones. In addition, plant tumors are characterized by excessive multiplication of cells, but without invading neighboring cells or surrounding tissues. Plant tumors are caused by infections or trauma that cause structural damage. Among the infections, bacteria and fungi predominate, but they can also be infected by viruses.

As for animals, many of the creatures that inhabit the blue paradise may suffer from cancer. From the largest and most ancestral, and before humans, such as dinosaurs, to the smallest such as the hydra. Those who have searched systematically have found animals more susceptible and others more resistant to cancer, but no animal has been found that is safe from the disease. Cancer occurs at astonishingly high rates and may be responsible for 40 percent of total deaths in multicellular animals across the spectrum from mollusks to mammals.

Studies on the prevalence of cancer in wildlife suggest that there is a spectrum of susceptibility to tumors in vertebrate animals. The highest prevalence of cancer is in mammals, followed by reptiles and birds. Frogs, toads and their amphibian companions enjoy the lowest prevalence of cancer. Among mammals, vulnerability to cancer varies from those that are extraordinarily resistant – among these lucky ones are two types of rats: the naked mole and the blind mole – to the other extreme, where there are animals that suffer from it with a higher frequency than the other groups have. Among these unfortunate experts cite Tasmanian devils, cheetahs, dogs, guinea pigs and ferrets. Human beings are neither those who suffer more cancer nor those who suffer less, we occupy an intermediate place.

Why is this happening? Why these differences? If cancer is a disease of cells that increases with age, we should think that animals that are larger (and therefore have greater numbers of cells) and those that live longer are those that would have more possibilities. And so it is within each species. Among humans, a tall person has a higher risk of cancer than a short person (a 10 percent higher risk with every ten centimeters difference in height). And cancer is a disease of the elderly. According to the National Cancer Institute: Older age is the most important risk factor for cancer in general and for many cancers in particular. Cancer incidence rates increase steadily with advancing age, from less than twenty-five cases per hundred thousand people in the age groups under twenty, to about three hundred and fifty per hundred thousand people between forty-five and forty-nine years, up to more than a thousand per hundred thousand people in the age groups of sixty years and older.

That means that, unless we find the elixir of youth (maybe one day we will have pills that repair DNA and contain telomerase, an enzyme that prevents the aging of chromosomes?), cancer will continue to be prevalent in humanity, and its figures, if we take into account that we live more and more years, can only increase with each generation.

• cancer