Blood protein linked to pancreatic cancer

NEW YORK (Reuters Health) - A blood protein related to body weight and physical exercise levels appears to be linked to pancreatic cancer risk, according to a new study.

The findings, say researchers, support the association of obesity and a sedentary lifestyle with an increased risk of pancreatic cancer, a cancer with a high mortality rate that is difficult to catch early.

Because of its grim prognosis, researchers are particularly interested in identifying the risk factors for pancreatic cancer so that more cases can be prevented. For the current study, investigators looked at whether blood levels of a protein known as IGFBP-1 were related to the risk of developing the cancer.

IGFBP-1 -- short for insulin-like growth factor binding protein-1 -- inhibits the activity of insulin-like growth factor-1 (IGF-1), a hormone that can assist the growth and spread of cancerous pancreatic cells.

The researchers followed participants enrolled in several large, ongoing clinical trials, such as the Nurses’ Health Study and the Physician’s Health Study. Levels of IGFBP-1 were measured in 573 subjects.

Four years later, 144 had developed pancreatic cancer.

The men and women with the lowest levels of IGFBP-1 were twice as likely as those with higher levels to develop pancreatic cancer, according to the report in the journal Cancer Research.

A number of studies have shown that obesity and lack of exercise may raise the risk of pancreatic cancer -- with the evidence being stronger for obesity. Low IGFBP-1 levels are typically found in obese and inactive individuals.

Therefore, the current findings indirectly support them as risk factors for pancreatic cancer, lead study author Dr. Brian M. Wolpin told Reuters Health.

Perhaps more importantly, the study points to a reason for the connection, according to Wolpin, an attending physician at the Dana-Farber Cancer Institute in Boston.

Since IGFBP-1 binds to and “sequesters” IGF-1, he explained, people with chronically low IGFBP-1 levels would have more “free” IGF-1 in the circulation, interacting with body cells. In theory, IGF-1 would be better able to promote the growth of pancreatic cancer cells.

Understanding the mechanisms underlying pancreatic cancer, Wolpin said, could aid in both preventing the disease and developing better treatments for it.

It’s too early, he said, to tell whether measuring IGFBP-1 levels, specifically, could help in detecting the cancer. But future studies should investigate this.

SOURCE: Cancer Research, August 15, 2007.