Featured Research

from universities, journals, and other organizations

Gene polymorphisms identified that are responsible for breast density and cancer risk

Date:
October 23, 2012
Source:
BioMed Central Limited
Summary:
It has long been known that breast density, or mammographic density, is a strong risk factor for breast cancer, and that estrogen and progestin hormone therapy increases dense breast tissue. Now, a study has identified several gene variants in hormone metabolism and growth factor pathways that may be associated with breast density and, hence, breast cancer risk.

It has long been known that breast density, or mammographic density, is a strong risk factor for breast cancer, and that estrogen and progestin hormone therapy increases dense breast tissue. Now, a study published in BioMed Central's open access journal Breast Cancer Research has identified several gene variants in hormone metabolism and growth factor pathways that may be associated with breast density and, hence, breast cancer risk.

Mammographic density relates to the fact that x-rays permeate different types of breast tissue in different ways, leading to white areas on the mammogram. Fatty tissue appears on the mammogram as relatively translucent, whereas dense breast tissue contains more stromal tissue and epithelial cells, appearing as white areas. Women with a breast density of 75% or more have a 4-5 times higher risk of developing breast cancer than women of the same age with little or no density.

Controversy exists over why breast density is a cancer risk. Many studies suggest that density is at least partially inherited, and twin studies show that genetic factors do play a role in the variation observed. Breast density decreases naturally with older age and menopause, but also increases with hormone therapy. Merete Ellingjord-Dale and co-authors, from academic centers in Norway and Los Angeles, set out to investigate which genes could play a role in determining breast density. Because of the clear involvement of hormones, they were looking particularly for genes involved in hormone metabolism.

Using data from 2,036 women who participated in the Norwegian Breast Cancer Screening Program in 2004, and separating the participants into hormone therapy users and non-users, the authors found that different gene variants appeared to be important depending on the women's hormone therapy usage.

There was evidence to suggest that variants in the prolactin (PRL) gene were associated with breast density in users of estrogen and progestin, as well as norethisterone acetate (a common regimen in Nordic countries). In non-users of hormone therapy, variants in the tumor necrosis factor (TNF) and SULT1A1/2 genes were significantly associated with breast density.

The findings suggest that several genes in hormone metabolism and growth factor pathways are indeed implicated in determining breast density, and might increase breast cancer risk. Commenting on the findings, lead author, Merete Ellingjord-Dale said, "One reason it has been so difficult to pinpoint which genes are responsible for mammographic density is that the effect of some genetic variants may be amplified in combination with hormone therapy. Consequently in the presence of hormone therapy these genes cause increased density."

She continued, "It is important to consider both the genetic and non-genetic factors simultaneously. Exploring the functional role of gene variants associated with mammographic density could further clarify the biological mechanisms involved. "


Story Source:

The above story is based on materials provided by BioMed Central Limited. Note: Materials may be edited for content and length.


Journal Reference:

  1. Merete Ellingjord-Dale, Eunjung Lee, Elisabeth Couto, Ali Ozhand, Samera A Qureshi, Solveig Hofvind, David J Van Den Berg, Lars A Akslen, Tom Grotmol and Giske Ursin. Polymorphisms in hormone metabolism and growth factor genes and mammographic density in Norwegian postmenopausal hormone therapy users and non-users. Breast Cancer Research, 2012 (in press) [link]

Cite This Page:

BioMed Central Limited. "Gene polymorphisms identified that are responsible for breast density and cancer risk." ScienceDaily. ScienceDaily, 23 October 2012. <www.sciencedaily.com/releases/2012/10/121023204634.htm>.
BioMed Central Limited. (2012, October 23). Gene polymorphisms identified that are responsible for breast density and cancer risk. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2012/10/121023204634.htm
BioMed Central Limited. "Gene polymorphisms identified that are responsible for breast density and cancer risk." ScienceDaily. www.sciencedaily.com/releases/2012/10/121023204634.htm (accessed August 29, 2014).

Share This




More Health & Medicine News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain it. Video provided by Newsy
Powered by NewsLook.com
Amid Grave Ebola Estimates, US to Test Vaccine

Amid Grave Ebola Estimates, US to Test Vaccine

AP (Aug. 28, 2014) The National Institutes of Health will start the first human safety trials of an experimental Ebola vaccine next week, amid a grave estimate from the World Health Organization that Ebola cases in West Africa could top 20,000. (Aug. 28) Video provided by AP
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:
from the past week

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