Study to Look At Links Between Insulin, Sexual Hormones And Risk of Breast Cancer

BUFFALO, N.Y. -- Paola Muti, epidemiologist and assistant professor of social and preventive medicine in the University at Buffalo School of Medicine and Biomedical Sciences has received a two-year $238,000 grant to conduct the first major study of the relationship between breast-cancer risk and levels of insulin in the blood.

She also will investigate breast-cancer risk and its association with levels of male sexual hormones, or androgens; female sexual hormones and insulin-like growth factor 1 (IGF-I), a protein that promotes changes in breast cells.

The grant was awarded by the United States Army Medical Research and Material Command.

Muti, who has been researching the role of hormones in the development of cancer, showed in an earlier study that women with certain physical characteristics linked to high levels of testosterone, the most active androgen, may have a greater risk of developing breast cancer than women without these characteristics.

Her current study, building on her previous research, aims to show that the risk of developing breast cancer is associated with various hormonal conditions: increased insulin levels in the blood; increased bioavailability of IGF-1; increased levels of androgens, specifically total and free testosterone, and increased levels of estrogens, specifically total and free estradiol.

Muti also hopes to show that the increased bioavailability of IGF-1 and the higher concentrations of the sexual hormones are caused by higher insulin levels.

Blood samples to be used in this study were collected from participants recruited into the ORDET study, a prospective study conducted in Northern Italy that provides a large biological specimen bank. Muti directed that project and serves as co-investigator.

"We expect to observe higher insulin levels, higher IGF-1 bioavailablilty and higher sex steroid levels in blood samples from participants who later developed breast cancer than in blood samples from a control group of women who did not develop the disease," Muti said.

The Italian National Cancer Institute in Milan and Teresa Quattrin, M.D., UB associate professor of pediatrics and director of the Diabetes Center at Children's Hospital of Buffalo, are collaborating on the study.