Most of us thought that cancer is not transmissible. However, there are some exceptions such as a species of shellfish which was recently discovered to carry a type of cancer that is somehow transmitted from a specimen to another.
Until now, scientists observed the sexually transmitted venereal tumors in dogs and the facial tumors of Tasmanian devils. Cancer discovered in shellfish is the third exception ever recorded in history.
Stephen Goff, the scientist from Columbia University Medical Center, found last year a rare type of cancer which was established as transmissible. This kind of disease is very much like leukemia and was observed in soft shell clams from the water of the Atlantic coast.
This contagious type of cancer has spread among many shellfish specimens. After analyzing the possible causes of this plague, Goff came to the conclusion that the malignant cells are carried by the water until they find a host which they infest.
In other words, this disease is not only transmissible among the specimens of a single species but also from one species to another. After collecting samples of tumor cells DNA from carpet shell clams, cockles, and mussels around the coasts of Spain and Canada, Goff and his team learned something interesting.
The DNA of the tumor cells and the DNA of their host were different this time despite the fact that tumor cells and their host usually have the same DNA, making them hard to identify. In other words, this distinct type of DNA was present in every sample, just like a contagious disease.
Thanks to the fact that researchers learned the pattern of the tumor cells, they investigated the DNA and found out that it was present in other species as well. This means that this deadly cancer was transmitted between many species.
Furthermore, scientists believe that when shellfish die or defecate, the malignant cells reach the water, and they are carried by it until they find another host. They can survive in the water up to a couple of hours until they are consumed by another clam, cockle, or mussel.
Nevertheless, Goff stated that it was good news that they found out about this contagious type of cancer. Now, they can further investigate the problem in order to find the best strategy to prevent it from spreading to other species of fish and even humans.