New Breast Cancer Genes Identified

6 More Genes Linked to Increased Risk

Medically Reviewed by Charlotte E. Grayson Mathis, MD
From the WebMD Archives

June 13, 2002 -- Scientists have discovered six more abnormal genes that can increase the chance of developing breast cancer. The new findings may one day lead to new drugs that are more effective than the treatments currently available.

And the finding, appearing in the June 13 online edition of the journal Science, may lead to more tests that are able to screen for inherited breast cancer.

"Just as women today can be tested for BRCA1 and BRCA2 [gene] mutations to determine if they have an inherited predisposition for breast cancer, testing for mutations in these other six genes may soon become a routine part of gauging inherited breast cancer risk," says study author Alan D'Andrea, MD, of the Dana-Farber Cancer Institute in Boston, in a news release. "Women and their doctors can then use the information in deciding how to keep that risk at a minimum."

BRCA1 and BRCA2 are the names given to the first two genes discovered to be linked to breast cancer.

Prior research has found that between 50% and 85% of women with abnormal BRCA1 or BRCA2 genes will develop breast cancer by age 70, compared with the roughly 11% lifetime risk that the average American woman faces. But these genetic markers only explain a small number (about 5% to 10%) of all breast cancer cases.

The study shows that a defect or mutation in any of the half-dozen genes involved in causing a rare childhood blood disease known as Fanconi anemia can increase a person's chance of developing breast cancer.

Fanconi anemia is an extremely rare condition in which the bone marrow fails to produce enough blood cells to meet the body's needs.

Children born with the condition often require a bone marrow transplant to survive into young adulthood, and they are at risk for developing a variety of cancers including leukemia and tumors of the brain, breast, head and neck, colon, or other parts the body.

Researchers say the six abnormal genes that cause Fanconi anemia can trigger a chain reaction that hampers the normal activity of the BRCA1 and BRCA2 genes, which are responsible for repairing damaged DNA. If either of these genes isn't working properly or becomes damaged, DNA damage accumulates in cells and increases the chance that cells will become cancerous.

Researchers say by identifying the link between genetic mutations for Fanconi anemia and breast cancer, scientists may be able to develop new tests to determine who is at risk for inherited breast cancer and possibly create new treatments to correct the flawed genes.