The search for the familial breast/ovarian cancer gene.

Familial breast cancer is a very common autosomal dominant disorder in women. A predisposing gene for breast and ovarian cancer (BRCA1) has been mapped by linkage analysis to the long arm of chromosome 17. In almost all families with breast and ovarian cancer and half of those with only breast cancer, the disease is linked to this gene. The BRCA1 gene, which is also believed to be involved in sporadic breast and ovarian cancer, should soon be identified.