Featured Research

from universities, journals, and other organizations

Pregnant rats exposed to obesity hormone lose birth's protective effect on breast cancer

Date:
October 29, 2013
Source:
Georgetown University Medical Center
Summary:
Like humans, young rats that give birth have a reduced risk of breast cancer later in life. But a new study shows that this protective effect in animals is negated if they're exposed to an obesity-linked hormone during pregnancy.

Like humans, young rats that give birth have a reduced risk of breast cancer later in life. But a new study shows that this protective effect in animals is negated if they're exposed to an obesity-linked hormone during pregnancy.

The study, to be published online Nov. 1 in Cancer Prevention Research by Georgetown Lombardi Comprehensive Cancer Center scientists, suggests an important direction for research in women's health, particularly given obesity rates worldwide.

In humans, pregnancy initially increases breast cancer risk within the first five to seven years after birth, and then either permanently reduces the risk by nearly half in younger women, or increases the risk in women older than 30. The same pattern is seen in rats.

The link between obesity, pregnancy and breast cancer risk is only now being explored.

"We know that pregnant women who gain an excessive amount of weight have high blood levels of leptin -- a hormone made by fat tissue -- and that they have an increased risk of developing breast cancer after menopause," explains Leena Hilakivi-Clarke, PhD, a professor of oncology at Georgetown Lombardi, and lead author of the new study. "By studying these factors in animals, we hope to understand how they're linked."

For the study, the researchers looked at breast cancer risk after pregnant rats were exposed to leptin and what, if any, gene changes could be observed.

Their findings showed that similar to women, female rats had an initial increase in breast cancer risk after birth, but the risk eventually diminished to a level that was lower than in rats that did not give birth.

"This suggests pregnancy has a life-long protective effect against breast cancer in animals as it does in women," Hilakivi-Clarke explains.

But breast cancer risk in the rats exposed to leptin during pregnancy did not decrease. "This is concerning, as it suggests the exposure to the obesity-linked hormone negated the protective effect of birth on breast cancer risk."

To discover possible reasons for the differences in breast cancer risk, the researchers looked at gene patterns in the mammary glands of all the rats. "We saw a much different pattern among the rat groups," Hilakivi-Clarke says.

In women and animals, pregnancy permanently turns on genes that allow healthy breast cells to protect themselves against insults that can initiate cancer. These gene changes are believed to explain the dramatic drop in breast cancer risk in women who had a child before age 20.

"It appears that treating rats with leptin during pregnancy prevented the protective changes in genes from happening," Hilakivi-Clarke explains. "This work points to an important direction for research to prevent breast cancer in women since obesity is an epidemic," Hilakivi-Clarke concludes.


Story Source:

The above story is based on materials provided by Georgetown University Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sonia De Assis, Mingyue Wang, Lu Jin, Kerrie B. Bouker, and Leena A. Hilakivi-Clarke. Exposure to Excess Estradiol or Leptin during Pregnancy Increases Mammary Cancer Risk and Prevents Parity-Induced Protective Genomic Changes in Rats. Cancer Prevention Research, October 2013

Cite This Page:

Georgetown University Medical Center. "Pregnant rats exposed to obesity hormone lose birth's protective effect on breast cancer." ScienceDaily. ScienceDaily, 29 October 2013. <www.sciencedaily.com/releases/2013/10/131029133544.htm>.
Georgetown University Medical Center. (2013, October 29). Pregnant rats exposed to obesity hormone lose birth's protective effect on breast cancer. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2013/10/131029133544.htm
Georgetown University Medical Center. "Pregnant rats exposed to obesity hormone lose birth's protective effect on breast cancer." ScienceDaily. www.sciencedaily.com/releases/2013/10/131029133544.htm (accessed October 21, 2014).

Share This



More Health & Medicine News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC Revamps Ebola Guidelines After Criticism

CDC Revamps Ebola Guidelines After Criticism

Newsy (Oct. 21, 2014) The Centers for Disease Control and Prevention have issued new protocols for healthcare workers interacting with Ebola patients. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Vaccine Trials to Start a in January

WHO: Ebola Vaccine Trials to Start a in January

AP (Oct. 21, 2014) Tens of thousands of doses of experimental Ebola vaccines could be available for "real-world" testing in West Africa as soon as January as long as they are deemed safe in soon to start trials, the World Health Organization said Tuesday. (Oct. 21) Video provided by AP
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
Powered by NewsLook.com
CDC Issues New Ebola Guidelines for Health Workers

CDC Issues New Ebola Guidelines for Health Workers

Reuters - US Online Video (Oct. 21, 2014) The U.S. Centers for Disease Control and Prevention has set up new guidelines for health workers taking care of patients infected with Ebola. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins