In 1990, Geneticist Mary-Claire King and her colleagues at the University of California, Berkeley discovered BRCA1, the first gene for a hereditary form of breast cancer. That accomplishment helped explain why some women who carried mutations in this gene saw their lifetime risk for developing breast cancer rise from 8% to over 80%.

Although Dr. King and her colleagues at the University of California, Berkeley, did not clone the gene, they laid the groundwork for genetically testing at-risk women for BRCA1 to reduce or prevent malignancies from developing.