Reference News Network reported on June 26 that a study published in the journal Nature pointed out that cockles, clams and mussels can infect a cancer similar to human leukemia, resulting in the high mortality rate of these shellfish.
Antonio Villalba, professor emeritus of the Department of Life Sciences at the University of Hernaresburg in Spain, who participated in the research, pointed out that the cancer is not transmitted to humans, according to the European news agency on June 23.
The study, titled "Widespread Transmission of Independent Cancer Lineages Among Multiple Shellfish," demonstrates that at least four bivalve molluscs can infect leukemia-like spreading tumors and that cancer cells can spread between sick and healthy individuals.
Affected by this cancer include sea mantises living on the Atlantic coast of North America, commonly known as soft-shell clams and long-necked clams; oil black shell clams living in the northwestern United States and southwestern Canada; European birdtail clams and Galician golden carpet shell clams living in several European countries, including the Galicia region of Spain.
The study is the first to demonstrate that the infection of cancer cells between different individuals is more common in the marine environment, and for the first time, it proves that cancer cells can be transmitted between different shellfish.
Among vertebrates, however, only two animals can contract cancer through direct transmission of cancer cells, the Tasmanian (Australian) Devil, whose survival is already at risk for the spread of a facial tumor, and dogs, which infect granulomatous tumors.
Cancer begins to spread in shellfish when cancer cells leave the diseased individual and come into contact with the water. Professor Villalba stressed that the immune system of an individual who normally receives should be able to destroy cancer cells, but these cells are constantly replicating, causing the receiving individual to develop cancer.
Also involved in the study were The University of Henaresburg, Columbia University in the United States and other researchers from Canada.
Professor Villalwa explained that researchers have long known that many bivalve molluscs have leukemia-like spreading tumors. But in most shellfish, the tumor appeared in only a few individuals, but in the four shellfish studied, the tumor had a high incidence and a high fatality rate.
Of all the shellfish studied, cancer cells are clones of the same kind of independent cells that spread from diseased individuals to healthy individuals.
The study notes that while we eat cockles or clams with the disease, bivalve shellfish cancer doesn't spread to consumers because when these cancer cells get into our gastric juices, our immune system kills them.
The final report highlights that these studies provide new approaches to the study of infectious cancers. (Compilation/Lu Wang)