New Gene Tied to Added Breast Cancer Risk

Icelandic women with a bad gene that raises their risk of breast cancer were virtually certain to develop the disease if they also had a mutation in a second gene, scientists reported, and researchers believe the discovery will help unravel the genetic underpinnings of the most common cancer in women worldwide.

Two genes discovered a decade ago - BRCA1 and BRCA2 - have been linked to hereditary forms of breast cancer. Women with one of them have 3 to 7 times the risk of developing the disease compared with women who lack such genes. And scientists long have searched for other genes that may act alone or with them to raise risk. Now one called BARD1, appears to do that.

More surprisingly, the risk of developing breast cancer roughly doubled for women with the BARD1 mutation and the BRCA2 mutation most common in Iceland. "When you get them together you basically have almost certainty of breast cancer," scientists say.

In the United States, BRCA1 is more common than BRCA2, especially among Ashkenazi Jewish women. Many women with one of these bad genes agonize over whether to have mastectomies or other preventive treatments.

"A lot of people don't really want to deal with these issues unless they've had breast cancer" and are worried about it returning, said Ronit Elk, a prevention researcher at the American Cancer Society. If more research bears out the role of BARD1, women might be able to make better decisions, she said.