The war on cancer just got some new intelligence data on the enemy that makes the battle scarier and much tougher to win. Researchers have discovered a strain of the disease that can be transmitted between different species. Should we be worried?
It’s a known fact that a few cancers can pass between members of certain species, as shown recently in the case of Tasmanian devils where a parasitic facial cancer has wiped out 70 percent of the species in just 20 years. Another cancer, canine transmissible venereal tumor (CTVT), has been found to pass from dog to dog for over 11,000 years, making it the oldest living cancer. Fortunately, these cancers stay within their host species and all other cancers apparently die within their host without being transmitted.
Until now. Molecular biologist Stephen Goff of the Columbia University Medical Center was studying another creature that passed cancer among its members – mussels – when he noticed that the cancer cells and the mussels' cells didn’t have the same DNA. That meant they were passed to it from another species.
Further research found that this leukemia-like cancer affected mussels from Canada and cockles and golden carpet shell clams from Spain. Genetic analysis of the cancerous tumors in the creatures confirmed the cancer came from other species.
How is this happening? Bivalves like mussels, cockles and clams are known to have simple immune systems that are ill-equipped to fight off new or unusual invasive cells pulled into their systems by their feeding filters. It’s suspected that the cancer cells are released into the water after a bivalve dies and easily sucked into a new host.
Does this mean that sharks are no longer the creature to be feared at the beach? It is if you’re a bivalve, says Elizabeth Murchison of the Cambridge Veterinary School.
These findings seem to paint a picture of shellfish beds around the world that are awash with microscopic cancer cells metastasizing both within and between species.
What about other species? Goff is not optimistic.
I guess that many, many of the cancers that are known will turn out to be of this [contagious] type. How many other marine species might turn out to suffer from this, we don't really know.
And humans? It appears the cancer requires that the different species have some similarities in order to be transmitted.
So unless you’re a bottom-feeding, unhealthy beach bum, you’re safe. Sound like anyone you know?