Featured Research

from universities, journals, and other organizations

Possible clues to tamoxifen resistance in breast cancer patients

Date:
March 30, 2011
Source:
Journal of the National Cancer Institute
Summary:
Breast cancer patients who become resistant to tamoxifen may have low levels of a protein called Rho GDI-alpha, according to a new study.

Breast cancer patients who become resistant to tamoxifen may have low levels of a protein called Rho GDI-alpha, according to a study published online March 30 in the Journal of the National Cancer Institute.

Related Articles


Women whose tumors have estrogen receptors (ERs) often take tamoxifen after surgery to prevent recurrence of the cancer and keep it from metastasizing to other parts of the body. Some patients, however, become resistant to the drug even though their tumors remain ER-positive.

To explore the mechanisms of this resistance, Suzanne Fuqua, Ph.D., professor of medicine in the Lester and Sue Smith Breast Center at Baylor College of Medicine in Houston and colleagues compared two groups of ER-positive tumors: four primary tumors from women who took tamoxifen and did not have a recurrence and five metastatic tumors from women taking tamoxifen whose tumors spread while they were on the drug. The authors found that Rho GDI-alpha was under-expressed -- its levels were low -- in the women with tamoxifen-resistant metastatic disease. They validated the association of low Rho GDI-alpha with tamoxifen resistance in laboratory cells, in human tumors implanted in mice, and in genetic data from 250 women whose ER-positive breast tumors were treated with tamoxifen.

They also found that levels another protein -- MTA2--rose markedly when Rho GD1-alpha dropped and that levels of MTA2 and Rho GDI-alpha combined predicted recurrence.

"These are the first data suggesting a tight, clinically important connection between the two pathways, Rho GDI-alpha and MTA2," the authors write. "Our data also suggest a possible mechanism, in which the loss of Rho GDI-alpha function promotes distant progression of breast tumors by triggering downstream molecules, such as MTA2, with metastasis-promoting activities."

In an accompanying editorial, Matthew J. Ellis, Ph.D. and Brian A. Van Tine, M.D. of Washington University in St. Louis note that other studies have found the proteins to be associated in various ways with breast cancer. But not all these previous findings are consistent with the findings of this study. "Thus, the status of Rho GDI-alpha as a marker of tamoxifen resistance is unclear," they write.

The editorialists also comment on the increasing number of genetic alterations emerging in breast cancer. "In the next several years," they write, "many entire breast cancer genomes will be published, revealing for the first time the enormous scale of the disruption of the human genome associated with the development of this disease." After that, they say, efforts to understand the functions of disrupted genes "will be essential for the next surge of progress."


Story Source:

The above story is based on materials provided by Journal of the National Cancer Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. I. Barone, L. Brusco, G. Gu, J. Selever, A. Beyer, K. R. Covington, A. Tsimelzon, T. Wang, S. G. Hilsenbeck, G. C. Chamness, S. Ando, S. A. W. Fuqua. Loss of Rho GDI  and Resistance to Tamoxifen via Effects on Estrogen Receptor  . JNCI Journal of the National Cancer Institute, 2011; DOI: 10.1093/jnci/djr058

Cite This Page:

Journal of the National Cancer Institute. "Possible clues to tamoxifen resistance in breast cancer patients." ScienceDaily. ScienceDaily, 30 March 2011. <www.sciencedaily.com/releases/2011/03/110330192204.htm>.
Journal of the National Cancer Institute. (2011, March 30). Possible clues to tamoxifen resistance in breast cancer patients. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2011/03/110330192204.htm
Journal of the National Cancer Institute. "Possible clues to tamoxifen resistance in breast cancer patients." ScienceDaily. www.sciencedaily.com/releases/2011/03/110330192204.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rural India's Low-Cost Sanitary Pad Revolution

Rural India's Low-Cost Sanitary Pad Revolution

AFP (Nov. 28, 2014) — One man hopes his invention -– a machine that produces cheap sanitary pads –- will help empower Indian women. Duration: 01:51 Video provided by AFP
Powered by NewsLook.com
Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
WHO Says Male Ebola Survivors Should Abstain From Sex

WHO Says Male Ebola Survivors Should Abstain From Sex

Newsy (Nov. 28, 2014) — WHO cites four studies that say Ebola can still be detected in semen up to 82 days after the onset of symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
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