Contagious cancer in sea life more common than first thought

27 Jun 2016

A new study into the direct transmission of cancer among some sea life has found that bivalves are quite prone to the problem – bizarrely, cross species transmission was noted, too.

Bivalves are marine organisms that exist inside two shells, such as clams, cockles and mussels. They’re cool, they taste great, but, unfortunately, they’re also prone to catching cancer off each other.

That’s according to Stephen Goff from Columbia University Medical Centre, who led a team of researchers investigating the relatively new findings that cancer can be contagious.

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Tasmanian Devils are known to transmit cancer directly to other Tasmanian Devils – it’s pretty horrid, too.

Dogs are the second mammals that exhibit the phenomenon and, last year, Goff revealed certain soft shell clams were the third example found in nature.

Goff was suspicious that it didn’t end there, though, so now his team’s paper in Nature broadens the field somewhat. Looking at mussels (Mytilus trossulus), cockles (Cerastoderma edule), and golden carpet shell clams (Polititapes aureus) collected from the coasts of Canada and Spain, the evidence was everywhere.

In each species, they found that cancers were caused by independent clones of cancer cells that were genetically distinct from their hosts, meaning they had been transmitted from something else.

Mussels (left) at taken at Copper Beach in West Vancouver, cockles (centre) and golden carpet shell clams collected in the ria of Arousa in Galicia

Mussels (left) at taken at Copper Beach in West Vancouver, and cockles (centre) and golden carpet shell clams collected in the ria of Arousa in Galicia

Weirdly, they also found that the carpet shell clam had infectious cells which came from a related but distinct species. The researchers concluded that this cancer was due to a case of cross-species transmission.

“Now that we have observed the spread of cancer among several marine species, our future research will investigate the mutations that are responsible for these cancer cell transmissions,” said Goff.

The illness, known as disseminated neoplasia, is a leukaemia-like disease that affects bivalves in many parts of the world.

There is no evidence that humans can catch it through eating the shellfish. So that paella is grand.

Main seashell image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic