How a contagious cancer spread among clams

Warty venus clams are from Venus. Credit:Alicia Bruzos and Seila Daz Costas.

A study published today in eLife shows that a blood cancer jumped from one clam to another and spread among clams in the Mediterranean Sea.

The findings suggest that human activities may be contributing to the spread of cancer among different species of bivalve shellfish.

Dogs, devils, and bivalves have been found to have cancer. People of the same species are usually affected by these diseases. There have been at least two cases of cancer spreading among bivalve species.

"We wanted to know if a leukemia-like blood cancer found in some bivalves also causes warty venus clams, which are found in the seas of southern Europe," says Daniel Garca-Souto, a researcher in genetics.

The researchers collected war ventyus clams from all over the world. They found a type of blood cancer in warty venus clams. One group of clams was found along the country's Atlantic coast, while another group was found in the Mediterranean Sea.

The team used a technique called whole-genome sequencing to show that the cancer started in a single clam and spread to other clams. The warty venus clam was found in the cancer. The striped venus clam was identified by comparing the unknown genetic sequence to a database of bivalve species.

The cancer had jumped from the striped venus clam to the warty venus clams, and further testing confirmed it.

The genetic similarity of the cancer cells found in warty venus clams in both the Atlantic Ocean and Mediterranean Sea suggests that human shipping activities may have transported the cancer from one region to another. The idea is supported by a previous study which showed that mussels carried a cancer across the Atlantic by hitching a ride on ships.

The team hopes to determine the age of the tumors in their clam specimen and to see how long cancer has been spreading among these species.

"Our work shows that cancer can jump between clam species," says senior author José Tubo. We need to keep studying and monitoring the diseases that may pose a threat to the marine ecology.

A single clonal lineage of transmissible cancer has been identified in two marine mussel species in South America and Europe. There is a DOI: 10.7554/eLife.

The journal has information on eLife.

How a contagious cancer spread among clams was retrieved fromphys.org on January 18.

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