Abstract
Familial breast cancer has been linked to the D17S74 locus on chromosome 17q. To confirm this finding and to investigate whether ovarian cancer is also linked to this locus, five large families with a hereditary predisposition to cancer of the breast and ovary were investigated. Three families were positive for linkage. For the largest family the lod score was 2·72. These findings suggest that the chromosomal region 17q12-q23, previously shown to contain a gene for early-onset breast cancer, is also associated with a proportion of hereditary ovarian cancers.