Mary-Claire King has made contributions in several areas of genetics research, though she is perhaps best known for her insightful studies on breast cancer. Long before others considered cancer a genetic disease, King began pursuing the possibility of an inherited form of breast cancer by examining pedigrees of cancer patients. Her preliminary findings were encouraging and led to more specific molecular linkage analyses on families with large numbers of affected women. In 1990, King reported data confirming the long arm of chromosome 17 (17q21) as the location for a gene, now known as BRCA1, associated with a familial form of breast cancer. Although other collaborative groups eventually identified the gene itself in 1994, that work could not have been accomplished without Dr. King's initial contribution, and she went on to use her data to confirm the results of her colleagues. The ultimate cloning of BRCA1 and a second breast cancer susceptibility...