A contagious cancer is spreading in clams

The finding provides evidence that cancers may be spreading among different species of bivalves, and suggests that human activity may have inadvertently contributed to the spread of these cancers to new locations and species

Infectious cancers have been found in dogs, devils, and bivalves such as clams and mussels

"We set out to determine whether the leukemia-like blood cancers found in some bivalves also infect Venus verrucosa, also known as the wart clams, which are found in the oceans of southern Europe," Santiago de Composte said.

The researchers collected 345 warthorn clams from coastal areas of Spain, Portugal, France, Ireland and Croatia

Using whole-genome sequencing, the team revealed that the cancer originated in a single clam, became contagious, and spread among the clams

Further DNA testing of the mitochondria and nuclei of the cells of both clams confirmed that the cancer jumped from the clams to the clams

"The genetic similarities of cancer cells found in the Atlantic and Mediterranean clams suggest that human shipping activity may have spread cancer from one region to another," said co-first author Alicia Bruzos, who led the study on the study.

The team now hopes to conduct further studies to determine the age of the tumors in their clam specimens and to explore how long the cancer may have spread in these species

"Our work demonstrates that infectious cancers can jump between marine clams," concludes senior author José Tubío, a genome and disease researcher at the University of Southern California

Seila Diaz, Alicia L Bruzos, Daniel Garcia-Souto, Sara Rocha, Ana Pequeño-Valtierra, Camila F Roman-Lewis, Juana Alonso, Rosana Rodriguez, Damian Costas, Jorge Rodriguez-Castro, Antonio Villanueva, Luis Silva, Jose Maria Valencia, Giovanni Annona, Andrea Tarallo, Fernando Ricardo, Ana Bratoš Cetinić, David Posada, Juan Jose Pasantes, Jose MC Tubio.