Research links DNA with colon cancer

By Craig Trudell (Last updated: 08/28/09 6:31pm) An MSU researcher working with a team of scientists discovered people carrying a certain genetic variation are more susceptible to colon cancer.

In a study that included MSU epidemiologist Joseph Bonner, researchers identified people who carry a marker on human chromosome 8 are 23 percent more likely to develop colon cancer.

The findings were published in the July issue of Cancer Biology and Therapy.

Through genetic testing of patients, doctors are able to look for variations linked to colon cancer and watch people who are at risk more carefully, Bonner said. When doctors find the cancer at an early stage, it can be removed.

"Unlike your brain, you can live without a few inches of your colon," he said. "This research is going to save lives."

One of the main problems with colon cancer is the lack of symptoms patients experience, said Rick Jennelle, a cancer expert at University of California, Davis.

"If you have a tool that helps you find people that are at a higher risk, it allows you to bring those people in for more frequent testing," Jennelle said. "If you're able to detect the cancer early, it's fairly easy to take care of."

The research team, made up of scientists from Israel and the University of Michigan, found the genetic link after evaluating the genetic makeup and family history of about 2,000 colon cancer patients and comparing them with a similar population of healthy patients.

The link was a "hot spot" found in a region of human chromosome 8, U-M pathology Professor Joel Greenson said, another member of the research team. The researchers have yet to find the specific gene, or tiny fraction of the chromosome that accounts for the increased risk, but plan to zero in on it, he said.

"Right now, it's like we're looking at a map from 20,000 feet, but we don't know exactly what the street address is," Greenson said. "These findings are a starting point for us to come up with ways to identify the gene, then come up with prevention and treatment methods. That's the dream."

Bonner joined the Michigan-Israeli team in 1998, while finishing his master's degree in the MSU Department of Epidemiology. He used data from the early stages of the study for his master's thesis.

The team is a product of the ongoing Molecular Epidemiology of Colorectal Cancer project, which has searched for clues to a genetic tie to colon cancer in Israel, where colon cancer is the leading cause of cancer-related deaths.

The American Cancer Society estimates colon cancer will account for 50,000 deaths in 2007, and 150,000 new cases of colon cancer will be diagnosed this year.

More than 5,000 new cases of colon cancer are diagnosed in Michigan every year, according to the Michigan Department of Community Health.

The July issue of the scientific journal Nature Genetics reported three other research teams searching for a genetic link to colon cancer have come across the same chromosome. The chromosome may also be linked to a higher risk for other cancers, U-M epidemiologist Stephen Gruber said in a statement.

"The same genetic region that predisposes to colon cancer also has recently been shown to be an important region predisposing breast cancer and prostate cancer," said Gruber, the co-leader of the Michigan-Israeli team.

Craig Trudell can be reached at trudell6@msu.edu.

Originally Published: 07/17/07 12:00am