Скачать или смотреть Cancer cells floating around in our seas and oceans! SCUBA CANCERS project

Marine waters from our seas and oceans are full of minute organisms such as fungi, algae, bacteria, and… cancer cells.

Yes, you heard right. In some cancers, tumour cells behave as parasites that can be directly transmitted between individuals.

Despite cancer contagion being a rare event, transmissible cancers seem to be common under the sea.

Marine bivalves such as clams, cockles and mussels can transmit a type of blood cancer called hemic neoplasia, which is characterized by the uncontrolled proliferation of blood-like cells. Eventually, these cancer cells can leave the host that spawned them and live in the marine environment until they infect a new host, spreading across bivalve populations.

The European-funded project SCUBA CANCERS investigated the prevalence of hemic neoplasia in the Warty venus, a saltwater clam found in the Atlantic Coast of Europe and the Mediterranean Sea.

We collected and examined more than four-hundred clam specimens from eight sampling points across five countries in the Seas of Europe, including Spain, Portugal, France, Ireland and Croatia.
This screening found a number of clam specimens infected with this cancer in two regions from Spain: one in Galicia, in the Atlantic Ocean coast, and another in the Balearic Islands, bathed by the Mediterranean Sea.

We sequenced and partially reconstructed the genomes from the tumours, which revealed the presence of DNA sequences from two different species.

This unexpected finding suggested cross-species transmission of cancer in the Warty Venus from a second, unknown species. Thus, what was the cancer-donor species name? Consultation of genetic databases and further genomic analyses determined that tumour cells belonged to a clam species called Striped Venus, which cohabits with the Warty venus in the Seas of Europe.

Our findings confirm that marine transmissible cancers can jump between species, representing a potential threat for the ecology of the marine environment, and point out the necessity of their identification and genetic characterization for their monitoring and prevention.