Dr. Nomelí Nuñez, Assistant Professor in Nutritional Sciences, was awarded a grant from the American Cancer Society and National Cancer Institute to study the relationship between obesity, insulin and inflammation in postmenopausal breast cancer.
In postmenopausal women, obesity increases the risk of developing and dying from breast cancer. The population of obese adult women has increased dramatically in the United States, from approximately 16 percent in 1962 to more than 34 percent today. The dramatic increase in obesity, combined with the fact that more than 75 percent of new cases of breast cancer occur in postmenopausal women, increases the likelihood that the harmful impact of obesity on breast cancer will continue to rise.
Why obesity increases breast cancer risk is not well known. We do know, however, that obesity can cause a condition called insulin resistance, which is a state of reduced responsiveness of tissues to the physiological actions of insulin, consequently resulting in a rise in blood insulin levels and, eventually, diabetes.
The hypothesis is that insulin resistance, rather than excess fat or the factors produced by fat cells, is the key target for disrupting the obesity-cancer link. Animal studies will fill important gaps in our knowledge of the obesity-breast cancer relationship because they will determine how fat cells and insulin resistance affect breast cancer development in the absence of estrogen (post-menopause).
These studies are unique in this respect, since most published animal studies examining the obesity-breast cancer relationship have failed to take menopausal phase into consideration. This is an important distinction, however, since the majority of women who get breast cancer do so after menopause.
By examining the roles fat cells and insulin resistance have on breast cancer development, in the context of ovarian function (e.g., presence of estrogen), we will be able to use breast cancer animal models more effectively, and what we learn from these models will be relevant to post-menopausal women. Moreover, results from our studies, especially those involving estrogen (post-menopause), and insulin-like growth factor 1 (to examine insulin resistance), could serve as the basis for the development of more specific targets to prevent and treat breast cancer.
