Social Isolation Actually Spurs Growth of Cancer

My apologies for the absence of new blog posts over the first part of October. My travel schedule was rough; at one point, I delivered one presentation each day while traveling to various universities on the East Coast, from the University of Maryland (Baltimore) to Virginia Commonwealth, Virginia Tech, Duke and UNC Chapel Hill. The Sham vs. Wham publication schedule at this point will go back to normal.

Recently a study was published in Cancer Prevention Research (a journal of the American Association for Cancer Research) which explored the health dangers of being isolated socially. It turns out that one's social environment can play an important role in the biology of disease, including breast cancer, and lead to significant differences in health outcomes.

"This study uses an elegant preclinical model and shows that social isolation alters expression of genes important in mammary gland tumor growth,” said the journal’s Deputy Editor, Dr. Caryn Lerman. The studies were done in mice, in a "model system" set up to mimic what happens in the human body.

Previous results from clinical studies have indicated that social support can improve the health outcome of patients with breast cancer. Epidemiological studies have suggested that social isolation increases the mortality risk from several chronic diseases, and not just breast cancer.

Author Suzanne D. Conzen, M.D. (University of Chicago) along with colleagues from the Institute of Mind and Biology at the same university, evaluated whether an unfavorable social environment could influence tumor growth in mice that are genetically predisposed to mammary gland cancer. They found that female mice that were chronically stressed because of social isolation (from the time they were first separated from their mothers) developed significantly larger mammary gland tumors compared to those mice that were group-housed. Additionally, the isolated mice developed a heightened corticosterone stress hormone response.

“... Living in the stressful environment was associated with greater tumor size, suggesting that the social environment may in fact alter the biology of cancer growth," Conzen said. Further research is needed to focus on which specific cell types the changes in gene expression are taking place. This knowledge could potentially lead to interventions that block similar pathways favoring the growth of human breast cancer.

Dave