The Genetics of Breast and Ovarian Cancer; Women's Health; Scientific American Presents; by Brown, King; 3 Page(s)

What if you could gaze into a crystal ball and learn that breast or ovarian cancer lies in your future? It's a frightening possibility-and one women who come from families with the cancers now face. Today's crystal ball is a high-tech blood test. Analyzed in a lab, the DNA in your white blood cells can reveal mutations in two genes, BRCA1 and BRCA2, that put you at great risk for familial breast or ovarian cancer. And that's the easy part. It's then up to you to make tough health decisions-whether getting frequent mammograms and ultrasound exams of your ovaries or opting for radical surgery to remove your breasts or ovaries.

Scientists discovered BRCA1 in 1994 and BRCA2 a year later. Now they are unraveling how the genes work-and why they sometimes don't. One researcher at the forefront is MARYCLAIRE KING, Ph.D., a molecular geneticist at the University of Washington. King has analyzed mutations in BRCA1 and BRCA2 in hundreds of families. She speaks with KATHRYN SERGEANT BROWN, special correspondent for SCIENTIFIC AMERICAN, about the genetics of breast and ovarian cancer. One of King's most important messages is that most breast cancers are not caused by inherited mutations.