Social isolation and stress can raise breast cancer risk
September 03, 2015
Joining McClintock and Hermes in preparing the PNAS paper were Bertha Delgado, researcher at Ben Gurion University, Israel; Maria Tretikova, Resident in Pathology at the University of Chicago Medical Center; Sonia Cavigelli, Assistant Professor of Biobehavioral Health at Penn State University; Thomas Krausz, Director of Anatomic Pathology at the University; and Suzanne Conzen, Associate Professor of Medicine at the University. The National Institute of Environmental Health Sciences/National Cancer Institute, the U.S. Department of Defense, and the State of Connecticut Department of Mental Health and Addictive Services supported the research.
The paper is part of a series published by McClintock and her colleagues using animal models to study the onset of cancer.
Rats provide an excellent model for studying human health. They are gregarious animals that are constantly interacting, with complex social relationships and shared care for their young. Additionally, isolation is a natural part of their social order, as a rat stands sentry at each colony and needs to be extremely vigilant to danger on behalf of the rest of the group.
A paper published by University researcher Jason Yee and colleagues showed that rats that developed reciprocal supportive relationships during stress, in which they both asked for help and gave assistance to others, were likely to live longer. That research was reported in "Reciprocal Affiliation Among Adolescent Rats During a Mild Group Stressor Predicts Mammary Tumors and Lifespan," in the journal Psychosomatic Medicine.
Hermes was lead researcher in a paper published in Developmental Psychobiology that isolation disrupts the development of puberty in rats by accelerating maturation of ovarian function while simultaneously delaying mammary tissue development. As a result, the rats are more likely to development mammary tumors. The work was in a paper, "Isolation and the Timing of Mammary Gland Development, Gonadarche and Ovarian Senescence: Implications for Mammary Tumor Burden."
In a paper in the American Journal of Physiology, Hermes and McClintock reported that isolation caused a more pronounced inflammatory disease response in females than in males. That work was published in the paper "Social isolation and the inflammatory response: Sex differences in the enduring effects of a stressor."
More recently, in a paper published in Cancer Prevention Research, Conzen and McClintock reported that social isolation of a genetic mouse model of human breast cancer resulted in larger mammary tumor growth. In a paper titled "A model of gene-environment interaction reveals altered mammary gland gene expression and increased tumor growth following social isolation," Conzen and McClintock showed that social isolation was associated with the increased expression of specific sets of genes involved in metabolism and inflammation.
Source: University of Chicago