Navigation Links
Prolonged maternal separation increased breast cancer risk in neonatal mice

PHILADELPHIA Young mice that experienced the psychosocial stress of prolonged separation from their mothers had a higher incidence and faster onset of breast tumors compared with young mice who did not experience this stressful life event. Specifically, neonatal mice separated from their mothers for a prolonged period of time developed mammary tumors twice as fast as mice that experienced short or no maternal separation.

The results of this study, conducted by Leslie Kerr, Ph.D., associate professor of biology and psychology at Trent University, Peterborough, Ontario, and colleagues, add to the increasing amount of research examining the effects of stress and other social experiences on cancer development. Much of this research has been published in Cancer Prevention Research, a journal of the American Association for Cancer Research.

"So far, we have not really understood, or really sifted through and found factors in the environment that cause a predisposition to the development of breast cancer, or any cancers," Kerr said. "For example, how does the environment or experiences of an animal, including humans, affect physiological function and how might that influence risk for developing breast cancer?"

Examining environmental effects related to breast cancer development is of increased interest because, like the brain, breast tissue develops postnatally. This means that changes in developmental environment including changes in hormonal activity may increase an animal's risk for developing breast tumors, Kerr said.

Social experiences are one of the keystones of life, according to Kerr. Two other studies published in Cancer Prevention Research within the last year explored whether social isolation- another psychosocial stress-affected breast cancer risk.

"The studies by Conzen et al and Schuler et al compared social housing vs. individual housing and its effect on breast cancer risk," Kerr explained. "Animals are born and reared in a group, so when they are isolated as an individual it is an environmental stress."

Both studies looked at mice at puberty that were housed individually compared with mice housed in groups. Conzen and colleagues found that social isolation altered the expression of certain genes, increasing tumor growth. Schuler and colleagues found that social isolation affected breast cancer development, but that the connection between environmental stressors and cancer may not be as clear as initially hypothesized.

Although the results of the two studies differed slightly, Kerr said that important result is that the environment, specifically the psychosocial environment, likely affects cancer risk.

"In contrast to these studies, ours was designed to show whether neonatal experiences, including either mild or moderate stress because of maternal separation experiences, affect normal breast development or predisposed the animal to carcinogen-induced breast cancer," Kerr said.

Kerr and colleagues examined how either brief maternal separation for 15 minutes daily or prolonged separation for four hours daily during the first three weeks of life influenced the development of normal and cancerous mammary gland development in female mice. These mice were compared with mice that did not experience any maternal separation.

When the mice reached puberty and young adulthood, the researchers measured the levels of estrogen receptor alpha and p53, the levels of which have been linked to breast cancer development in prior research. All the mice were then exposed to a known carcinogen in order to assess breast tumor incidence and invasiveness.

The researchers found that 300 days after exposure to the carcinogen 53 percent of the mice exposed to prolonged separation had developed palpable breast lesions compared with 20 percent of mice exposed to brief or no maternal separation. The cancers in mice with prolonged separation were also more invasive.

In addition, mice exposed to prolonged separation had 200 percent greater expression of estrogen receptor alpha levels compared with mice that had no separation, and 30 percent higher levels than mice exposed to brief separation. No differences in p53 expression were found between mice that were exposed to different neonatal conditions.


Contact: Jeremy Moore
American Association for Cancer Research

Related biology news :

1. Malnutrition increases risk of prolonged hospital stay
2. UB specialized exercise regimen shown to relieve prolonged concussion symptoms
3. Prolonged stress sparks ER to release calcium stores and induce cell death in aging-related diseases
4. Prolonged effects of a warming anomaly on grasslands
5. USF receives NIH grant to study implications of maternal infection as cause of autism
6. Maternal diet and genes interact to affect heart development
7. Key nutrient in maternal diet promises dramatic improvements for people with Down syndrome
8. UC Davis study confirms link between advanced maternal age and autism
9. Exposure to young triggers new neuron creation in females exhibiting maternal behavior
10. March of Dimes honors Dr. Gail Harrison for outstanding work in maternal-fetal nutrition
11. Maternal, paternal genes tug-of-war may last well into childhood
Post Your Comments:
(Date:10/29/2015)... , Oct. 29, 2015   MedNet Solutions , ... entire spectrum of clinical research, is pleased to announce ... Tech Association (MHTA) as one of only three finalists ... "Software – Small and Growing" category. The Tekne Awards honor ... have shown superior technology innovation and leadership. ...
(Date:10/29/2015)... , Oct. 29, 2015 Daon, a global ... it has released a new version of its ... North America have already installed ... also includes a FIDO UAF certified server component ... preparing to activate FIDO features. These customers include some ...
(Date:10/29/2015)... -- Connected health pioneer, Joseph C. Kvedar , MD, ... and wellness, and the business opportunities that arise from ... of Healthy Things . Long before health and ... Kvedar, vice president, Connected Health, Partners HealthCare, was creating ... from the hospital or doctor,s office into the day-to-day ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... QUEBEC CITY , Nov. 24, 2015 /PRNewswire/ - ... the request of IIROC on behalf of the Toronto ... this news release there are no corporate developments that ... price. --> --> ... --> . --> Aeterna Zentaris ...
(Date:11/24/2015)... ... November 24, 2015 , ... This fall, global software ... events in five states to develop and pitch their BIG ideas to improve health ... state are competing for votes to win the title of SAP's Teen Innovator, an ...
(Date:11/24/2015)... , November 24, 2015 ... recent market research report released by Transparency Market Research, ... expand at a CAGR of 17.5% during the period ... Testing Market - Global Industry Analysis, Size, Volume, Share, ... global non-invasive prenatal testing market to reach a valuation ...
(Date:11/24/2015)... SAN FRANCISCO , Nov. 24, 2015 /PRNewswire/ ... today announced that Emily Leproust, Ph.D., Twist Bioscience ... Piper Jaffray Healthcare Conference on December 1, 2015 ... Palace Hotel in New York City. ... . Twist Bioscience is on ...
Breaking Biology Technology: