ATHENS, Ohio -- Studies of a protein implicated in the development of skin tumors in fish could lead to a better understanding of a similar protein's role in breast and other human cancers, according to researchers at Ohio University.

Scientists have been exploring the role cyclin D, a protein that regulates cell replication, plays in the development and death of tumors found on walleye, a North American freshwater fish. The skin tumors, walleye dermal sarcoma, appear and disappear seasonally, says Don Holzschu, assistant professor of molecular biology at Ohio University and a lead researcher on the project.

First reported in a National Cancer Institute monograph in 1969, these tumors -- which appear in the fall and die during the spring spawning season -- seem to pose no health risk to humans, according to officials with Ohio Sea Grant. Walleye infected with the tumors have been reported in rivers and lakes throughout North America, including in Ohio, New York and Canada.

Researchers suspect infected walleye spread the virus that causes the tumors during the spawning season, when all the fish are grouped together. "It's just like sending your child to daycare," Holzschu says. "It's a perfect time to spread the virus." It's thought that the virus grows over the summer and tumors begin to appear in the fall. By spring, the tumors are dying and the infection is passed to other fish.

While the seasonal nature of the tumors is enough to keep the scientists' interest, new studies have added to their fascination with this project. In their analysis of the viruses that cause walleye dermal sarcoma and another skin disease, walleye dermal hyperplasia, researchers have discovered the culprits for these infections are three retroviruses that are unlike any ever studied.

A retrovirus is a virus that has RNA as its nucleic acid and uses the enzyme reverse transcriptase to copy its genome into the DNA, whic
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Contact: Melissa Rake
rake@ohio.edu
740-593-1891
Ohio University
3-Mar-1999