Cancerous tumors transmitted by infection!

Cancerous tumors live inside a patient’s body and spread until they are treated or kill the host, but some types of cancer have managed to make a qualitative leap by transmitting from one host to another, much like infectious diseases.

These types of tumors have been discovered in certain animals, such as dogs, oysters, and fish.

Until recently, doctors and researchers doubted that cancer could be transmitted through infection at all, but they are now beginning to discover that such tumors do exist, evolve, and spread. This has led some to wonder whether their spread is a rare occurrence or a common one that has simply gone unnoticed.

Joel Brown, an evolutionary ecologist at the Moffitt Cancer Center in Florida, U.S., told Knowable Magazine, a scientific research website, in remarks cited by the German News Agency (dpa) today, that cancerous tumors form when a cell within an organism abandons its normal role and begins to exhibit aggressive behavior toward the body, spreading, evolving, and treating the body as a host. In turn, the immune system fights these cancerous cells, which still resemble the body’s original cells.

Brown explains that the situation differs when a cancerous cell is transmitted to another host, as it then appears as a foreign entity that the new host’s immune system can recognize and target.

Researchers have found that these transmissible cancer cells employ diverse strategies to conceal themselves and thwart the defenses of the new host. Tumors that spread among certain species of oysters can disable genes associated with activating the host’s immune system, while some types of cancer that spread among dogs can hide their molecular identity signature, a type of protein called “MHC I,” thereby preventing the new host’s body from recognizing these cancerous cells as foreign.