CORVALLIS (AP) — Oregon State University scientists are using a strain of trout in cancer research, feeding them food laced with carcinogens as well as beneficial agents.

“They’ve definitely done their work in the war against cancer,” said Gail Orner, an assistant professor who often works with the Sinnhuber Aquatic Research Laboratory.

OSU has 30,000 fish at the facility east of town off Highway 34.

The university has been working with the fish for 40 years.

“We want to see what causes cancer in humans and what can prevent it,” Orner said. “There’s really nowhere else in the world that has the kind of water quality and facilities to be able to do this type of research.”

“It gives us the ability to do large-scale studies,” said Abby Benninghoff, an OSU toxicologist.

Although humans are more closely related to mammals, they share many biological traits with trout.

In some cases, such as aspects of liver cancer, fish are closer to humans than rodents in the way they react. Causes for cancer are very similar throughout organisms, even down to bacteria.

Since trout have a far lower natural rate of cancer than rodents, and they are cheaper to produce for studies.

“A tank of 100 fish costs the same to raise as one rat,” Orner said.

The latest published research from the facility found that PFOA, a chemical used in everything from plasticized cardboard food containers to waterproof clothing, increased the incidence of liver tumors in trout. It appears that it acts like an estrogen, which are known to promote certain cancers.

“We’re not really at this point saying it is a cause for concern in humans, but there certainly should be more study,” Orner said. “It’s widespread in the environment, and it’s even been detected in people. It’s being used less now than it has been, but it’s still very much around.”

Benninghoff will do follow-up studies with similar compounds.

The lab was set up in the 1960s to study an outbreak of liver cancer in hatchery trout. It turns out a compound from moldy peanuts in the fish feed, called aflatoxin, was causing cancer in the fish.

In developing countries, where up to 10 percent of the population dies from liver cancer, aflatoxin is a worry because people can’t necessarily afford to throw away moldy nut- and grain-based foods.

The largest cancer study ever done in vertebrate animals is continuing at the lab, to study the amount of aflatoxin that can cause cancer.

Researchers are about to complete the second of four segments in the study, which will include 50,000 fish. The project should last another year.