How Clams Provide Clues Into Cancer Evolution

The key to learning about cancer evolution in humans may be found by studying a surprising organism: the clam.

PNRI scientist Dr. Michael Metzger seeks to understand the principles of how cancer evolves and how some organisms can resist cancer by looking for discovery in an unexpected place through studying transmissible cancers in bivalves: mussels, oysters, cockles, scallops, and clams.

What is unique about this cancer compared to human cancers is that it is transmissible. The cancerous cells themselves spread from one animal to another, much like a virus.

“We don’t usually think of cancer as an infectious disease,” Dr. Metzger explains. “But several transmissible cancers have recently been found in the wild, some of which kill entire populations—and marine bivalves appear particularly susceptible.”

What does transmissible cancers in clams have to do with human health?

The bivalves serve as a model organism to study how cancer evolves and how some hosts resist succumbing to the cancer. This research can then be applied to understanding how cancer evolves in humans and how some people remain healthy in the face of a risk for developing cancer.

“If successful, we will come away with a far better understanding of how to prevent these transmissible cancers from decimating vulnerable marine species, and potentially uncover more clues about how cancer develops in humans,” says Dr. Metzger.

The National Science Foundation recently awarded Dr. Metzger a five-year, $3 million grant to investigate how cancer is transmitted among soft-shell clams on the Atlantic Coast and basket cockles on the Pacific Coast of North America. Although this grant is focused on the ecological health of the bivalves, the research conducted will garner insight that is applicable to other species.

Years from now, we might be thanking a clam for saving the life of our loved one from cancer.