An example of a Tasmanian devil shows that cancer can be a contagious disease in humans.

Tasmanian devil

Research scientists , described in several recent scientific papers, suggest that cancer can develop the ability not only to start metastasis to neighboring organs, but also transmitted from one person to another.

Despite long and persistent searches, a cure for cancer has not yet been found. Inhibits research and the fact that there is no generally accepted idea of ​​the causes of the appearance in the human body of malignant tumors. But some scientists are already trying to look into the future of the disease.
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Now, if a tumor appears in the body, it begins its “life” from scratch, and, developing, destroys its carrier (if it is not removed in time). In the next organism, the tumor starts all over again. If, however, to believe the opinion of researchers, then there may be such types of cancer that travel from carrier to carrier, evolving and improving along the way.

So far, such cases have not been recorded in humans. True, similar incidents have already happened: one laboratory technician injected with a syringe with tissue samples, and a tumor developed in his hand. Another physician, a surgeon, cut himself during an operation on a patient with a cancer. Naturally, there have been cases of cancer transmission during organ transplantation or during pregnancy, from mother to fetus.

The history of the transmission of cancer between animals is a bit richer. For example, in laboratory experiments, mosquitoes were able to transfer cancer cells between hamsters. But in dogs, there is a form of sexually transmitted cancer, which, as scientists think, first appeared more than 11,000 years ago.

It is believed that such a cancer has developed due to a rather long sexual intercourse that takes place between animals - but some researchers argue that it was a new type of cancer that could somehow influence the lengthening of this process in order to travel freely from one organism to another.

Another type of contagious cancer exists in cute animals called the Tasmanian devil (or marsupial devil). During numerous fights between individuals, cancer is transmitted through wounds on the face . Emerging tumors threaten this species with extinction.

Interestingly, in December 2015, specialists from Cambridge and the University of Tasmania published a study that described the discovery of a second type of cancer , transmitted between individuals of Tasmanian devils. How two genetically different types of contagious cancer appeared in their bodies remains incomprehensible.

According to one version, due to the small size of the population, their genetic diversity is so small that foreign cancer cells that entered the body were not detected by the immune system and freely mutated into something else. And another version claims that the appearance of contagious types of cancer is not such a rare occurrence in nature, and that it is necessary to pay close attention to the study of this possibility.

Cancer may exist just as long as multicellular organisms, and the relatively short life of individual individuals prevents the occurrence of a common form of contagious cancer - otherwise cancer would be a widespread phenomenon. In any case, this line of research looks quite promising.