Local chemical signals released by fat cells in the mammary gland appear to provide a crucial link between exposure to unrelenting social stressors early in life, and the subsequent development of breast cancer, researchers from the University of Chicago report in the July 2013 issue of the journal Cancer Prevention Research.
Some forms of stress exposure may be associated with an increased risk of certain types of aggressive breast cancer. But the mechanisms linking the biology of social stress to cancer have been hard to identify.
To unravel that mechanism, the researchers looked for differences between mice raised in small groups and those that grow up in an isolated setting — an established model of chronic stress without social supports.
“We found that exposure to the stress of social isolation leads to reprogramming of genes in fat cells in the mammary glands,” said study author Suzanne Conzen, MD, professor of medicine at the University of Chicago. “These fat cells then secrete substances that cause nearby pre-cancerous epithelial cells to proliferate more rapidly, accelerating the development of breast cancer. This local effect of fat cells in the breast was completely unanticipated.”