Fred Hutchinson Cancer Research Center scientists will help lead a national study on the link between two of the nation's major health problems — obesity and cancer.

Sponsored by the National Cancer Institute, the five-year, $54 million project will involve several medical centers, including "The Hutch," and thousands of research subjects.

Researchers already have found that more than half the adult population in the U.S. is considered overweight or obese, and that the association between obesity and cancer has grown stronger.

"We will learn a lot more about the mechanisms that link obesity to cancer risk. And we'll test specific cancer-prevention strategies," said Dr. Cornelia Ulrich, a Hutch scientist who is co-leader of one of the five projects that will be done locally.

The Hutch, known for research on the relationship between diet and exercise and cancer risk, will use an $18 million grant to coordinate the national initiative, called TREC (for Transdisciplinary Research on Energetics and Cancer).

Collaborating in the effort will be Case Western Reserve University in Ohio, the University of Minnesota and the University of Southern California.

Dr. Anne McTiernan, director of The Hutch's Prevention Center, will lead the local research, which will include more than 1,000 human volunteers.

She has conducted extensive research on preventing recurrent breast cancer and colorectal cancer through physical activity.

"We know there's an association between obesity, sedentary behavior and increased risk of certain cancers," McTiernan said in a statement. "Now we're trying to understand the link between cancer and obesity at a more fundamental, mechanistic level."

Some scientists have estimated obesity may be responsible for as many as a quarter of the cases of breast cancer and a third of colon-cancer cases, according to the International Agency for Research on Cancer.

Ulrich said the new research will include study of the effects of diet and exercise on humans and rats. Scientists will examine the cellular effects on the rats as they undergo the same routines and diets as humans, she said.

Research in The Hutch's portion of the initiative will center on five projects:

• Testing the effects of excessive glucose, or sugar, on cell growth and cell death.

• Analyzing the effects of interventions such as moderate calorie restriction and physical activity on indications of cancer development in rats. Colorado State University will collaborate in this effort.

• Examining the effects of high-glucose and low-glucose diets on the presence of blood indicators of cancer risk.

• Analyzing the effects of a yearlong exercise or diet program, or both, on indications of cancer development.

• Testing the effectiveness of an obesity-prevention project designed for the workplace.

Warren King: 206-464-2247 or wking@seattletimes.com