Gene Linked to Lower Breast Cancer Risk
Study Shows Genetic Variation Linked to Less Dense Breast Tissue
By Jennifer Warner
WebMD Health News
Reviewed by Laura J. Martin, MD
mammogram film

Jan. 31, 2011 -- A new genetic link may help identify women with less dense breast tissue who are at lower risk of developing breast cancer, according to researchers.

A new study shows women with a specific variation of the gene ZNF365 were more likely to have lower mammographic density or a low proportion of dense tissue vs. fat tissue in the breast, which has been linked to a decreased risk of breast cancer.

"Women with more than 75% dense tissue in the breast are at a fourfold to fivefold greater risk of breast cancer than women of the same age and body mass index (BMI) with little or no dense tissue," writes researcher Sara Lindström of the Harvard School of Public Health and colleagues in Nature Genetics.

A Visual Guide to Breast Cancer
Lower Breast Density

In the study, researchers analyzed genetic information from five previous studies with a total of 4,877 women. All of the studies included data on breast density measured by mammography screening and the women's genetic profile.

The results showed women with the gene variation named “rs10995190 A” were more likely to have lower breast density, even after adjusting for age and BMI. The researchers also replicated the genetic association in two additional groups made up of 2,835 women.

Researchers say this specific gene variation has already been associated with a lower risk of breast cancer in a recent study, and these results suggest that its role in affecting breast density may help explain this link. But further research is needed to confirm this association.