On Oct. 7, 1994, a strong candidate for the 17q-linked BRCA1 gene, which influences susceptibility to breast and ovarian cancer, was identified by positional cloning methods. Identification of BRCA1 should facilitate early diagnosis of breast and ovarian cancer susceptibility in some individuals as well as a better understanding of breast cancer biology.

The BRCA1 gene is expressed in numerous tissues, including breast and ovary, and encodes a predicted protein of 1863 amino acids. The findings were reported in Science.